Prasanna

MP Board Class 6th Special English Solutions Revision Exercises 3

Word Power

(a) Match the Columns.

Answer:
1. → (c)
2. → (j)
3. → (d)
4. → (b)
5. → (a)
6. → (h)
7. → (e)
8. → (i)
9. → (f)
10. → (g)

(b) Fill in the blanks with the help of given words.

(observe, judgements, stranger, bet, careless, worthy, bribe, dishes, pension, leader)

1. Kassim and Ali ………….. of marbles.
2. He gave his ………….. without fear or favour.
3. You must …………… a thing carefully before you describe it.
4. He does not know me. I am a ………….. for him.
5. Radha lost her books. She was very …………….
6. The king wanted to give the ring to the ……………. son.
7. The man tried to ……………. the clerk.
8. After retirement you will get ……………
9. When I visited her, she was washing
10. Robin Hood was the …………… of a company of outlaws.

Answer:

1. bet
2. judgements
3. observe
4. stranger
5. careless
6. worthy
7. bribe
8. pension
9. dishes
10. leader.

(c) Make sentences with the given words.
(virtue, challenge, wooden, innocent, native, trap, mercy, kingdom, nature, opportunity)
Answer:
Virtue           : Everyone praises him for his virtue.
Challenge     : The boy accepted the challenge.
Wooden       : A wooden house is very light.
Innocent       : The child is innocent.
Native           : He has gone to his native country.
Trap              : The elephant is trapped.
Mercy           : The criminal begged for mercy.
kingdom       : Everyone was happy in Akbar’s kingdom
Nature          : We see changes in nature.
Opportunity : It is a good opportunity to get my work done.

Comprehension

Question 1.
How did Kassim get back his ten marbles from Ali?
Answer:
Kassim said that his pencil could write any colour. Ali made a bet for ten marbles with him. Kassim took out his pencil. He recited some magic words. He wrote red, blue, yellow, green, orange on a piece of paper. Ali lost the bet. In this way, Kasim got back his ten marbles from Ali.

Question 2.
Why did Kassim think that Ali had cheated him?
Answer:
Kassim thought that Ali had cheated him. Ali had won nine marbles by asking him a riddle to which he himself did not know the answer. Kassim had given ten marbles to Ali. Ali returned one marble and saved nine.

Question 3.
Why did the old women go to the king?
Answer:
The old woman went to the king for justice.

Question 4.
How did Ramanna decide the case?
Answer:
Ramanna said to the thieves. “Bring your third companion and the pot will be, delivered only to three of you together.“ The thieves could, not locate their companion. They withdrew their case. In this way he decided the case in the old woman’s favour.

Question 5.
How did the rich man decide to honour the ring?
Answer:
The rich man decided to honour his ring. He told his sons that when he would be dying, he would give the ring to the worthiest of his sons. This son would inherit the family property and become the head of the family after the death of his father.

Question 6.
Why was Saladin in need of money?
Answer:
Saladin had spent all the money in wars and wasteful living. He found that his treasers had become empty. Therefore he was in need of money.

Question 7.
Why did Brahmadatta leave the city in disguise?
Answer:
Brahmadatta left the city in disguise to came through a man who could find fault in him.

Question 8.
Why did Mallika and his charioteer made way for Brahmadatta?
Answer:
King Mallika had to make way for King Brahmadatta as Brahmadatta was more righteous than him Man is worshipped and respected for noble deeds and righteous behaviour everywhere.

Question 9.
Why were the courtiers jealous of Birbal?
Answer:
The courtiers felt very jealous of Birbal as he (Birbal) was in the good book of the Emperor Akbar and enjoyed his favour.

Question 10.
What did Birbal say after returning from heaven?
Answer:
After returning from heaven Birbal said to Akbar that his ancestors had no barbers in heaven and they needed one immediately.

Question 11.
How did the courtiers get the barber’s cooperation?
Answer:
The barber got ready to cooperate with the courtier’s plan only after taking a large sum of money.

Question 12.
Why was Robin Hood a terror to the rich people?
Answer:
The rich people were afraid of Robin Hood, because he often robbed them of their money. He helped the poor with the booty.

Question 13.
When did Robin Hood get into the disguise of a butcher?
Answer:
While going to the town Robin Hood met a butcher on the way.

Question 14.
Why does the rain water have to struggle to come out of the spout?
Answer:
The spout is overflowing with water. Therefore, the rain water has to struggle for coming out of the spout.

Question 15.
Why did Columbus stop for some time at the Canary Islands?
Answer:
One of the ships of Columbus had lost her rudder on the way to the Canary Island. It was due to the mischief of the unwilling crew. Columbus could not sail forward. Therefore, he had to stop there for some time to get the ship repaired.

Question 16.
What reward had the king promised to Columbus and his crew?
Answer:
The king had promised a pension of ten thousand copper coins to Columbus and his crew.

Question 17.
How long did Columbus and his new sail before they reached the land?
Answer:
Before reaching land, Columbus and his sailors sailed for seventy days.

Question 18.
Why was the discovery of Columbus important?
Answer:
The discovery of Columbus more significant in a way that he had discovered a new continent i.e., America. He had in reality discovered the New World.

Question 19.
How did Ali catch the thief?
Answer:
Ali had put on the plate a liquid with a strong smell. All except the thief had touched the plate and their palms gave out the smell. The thief’s plain did not give out the smell which made if clear that he had stolen the gold.

Question 20.
What did Ali say to his followers after dinner?
Answer:
After dinner Ali told his followers to sit in a line in front of him.

Grammar

(a) Rewrite the sentences in reported speech.

Example: The teacher asked Mala if she would take part in school games.
The teacher said to Mala, “Will you take part in school games?”

1. She asked him if he was a doctor.
2. Lata asked him if it was his pen.
3. Mona asked her mother if she could cook idly for her.
4. Mohan asked his father if he had seen the Taj before.
5. The teacher asked her if she would attend the class the day after.

Answer:

1. She said to him, “Are you a doctor?”
2. Lata said to him, “Is it your pen?”
3. Mona said to her mother, “Can you cook idly for me?”
4. Mohan said to his father, “Did you see the Taj before?”
5. She teacher said to her, “Will you attend the class tomorrow?

(b) Combine the following pairs of sentences using so ………….. that.

Example:
The boy was very tired.
He could not climb the tree.
The boy was so tired that he could not climb the tree.

1. The fan is very high.
I cannot touch it.

2. The book was very difficult.
The students could not read it.

3. Her father was very poor.
He could not pay her fee.

4. Mala is very weak.
She cannot walk.

5. The weather is very cold.
We cannot go out.
Answer:
1. The fan is so high that I cannot touch it.
2. The book was so difficult that the students could not read it.
3. Her father was so poor that he could not pay her fee.
4. Mala is so weak that she cannot walk.
5. The weather is so cold that we cannot go out.

(c) Combine the sentences using Neither ……….. nor.

Example:
Akbar did not find any fault in him.
His ministers did not find any fault in him.
Neither Akbar nor his ministers found any fault in him.

1. Mohan doesn’t take tea.
He doesn’t take coffee.

2. Rekha did not know the answer.
Ashoka did not know the answer.

3. Hari did not help him
Rakesh did not help him.

4. I do not live in Delhi.
My teacher doesn’t live in Delhi.

5. India didn’t win the first test.
India didn’t win the second test.
Answer:
1. Mohan takes neither tea nor coffee.
2. Neither Rekha nor Askok knew the answer.
3. Neither Hari nor Rakesh helped him.
4. Neither I nor my teacher live in Delhi.
5. India won neither the first nor the second test.

(d) Put the given verb in present perfect continuous tense:

Example:
They (work) in this factory for the last three years.
They have been working in this factory for the last three years.

1. It (rain) for the last six hours.
2. The maths teacher (teach) in this school since 1095.
3. The boys (make) noise for the last three periods
4. The gardener (water) the plants since 9 o’clock.
5. She (sing) for the last one hour.

Answer:

1. It has been raining for the last six hours.
2. The maths teacher has been teaching in this school since 1995.
3. The boys have been making noise for the last three periods.
4. The gardener had been watering the plants since 9 o’clock.
5. She has been singing for the last one hour.

Let’s Write

(a) Write ten sentences about the town/village.
Answer:
Do yourself.

(b) Write a paragraph on “An Ideal Human Being” with the help of given hints: honest, speak the truth, kind, generous, faithful, good.
Answer:
An ‘Ideal’ man means a man of virtues. I know such a person is my neighbourhood. He is Mr. Philip who is really a nice person. He is kind to all. He behaves with everyone generously. He is faithful to his job. He is dutiful to his family and society. He is a religious man. Everyone loves him He is a good man in our society.

(c) Make a plan to spend your Christmas holidays and write it in a short paragraph.
Answer:
Vacation always gives us pleasure. We make plans to celebrate it. For the coming Christmas holidays. I have also chocked out some plans I have decided to go Shimla with some of my friends. We will stay there for a week. It will be an enjoying event for us all.

(d) Write five sentences on how you celebrated your birthday on the basis of given hints: invited friends, wear new clothes, cut the cake distributed toffees.
Answer:
I always celebrate my birthday with all joy and happiness. This year, on my birthday i.e., on 20 April. I invited all my friends. I wore new clothes. I distributed toffees among them. I was really a nice day for all of us.

MP Board Class 6th English Solutions

MP Board Class 9th Maths Solutions Chapter 7 Triangles Ex 7.4

Question 1.
Show that in a right angled triangle, the hypotenuse is the longest side.
Solution:
Given
ABC is a right angle A.
To prove:
AC > AB and AC > BC

Proof:
In ∆ABC
∠B = 90°
∴ ∠A + ∠C = 90° (by ASP)
and so ∠B > ∠A and ∠B > ∠C
AC > BC and AC > AB
(In a A, sides opposite to large angle are always longer).

Question 2.
In Fig. given below, sides AB and AC of ∆ABC are extended to points P and Q respectively. Also, ∠PBC < ∠QCB. Show that AC > AB.
Solution:
Given
∠PRC < ∠QCB To prove AC > AB

Proof:
In ∆ ABC
Exterior angle is equal to sum of two opposite angles
∠PBC = ∠1 + ∠3 and
∠QCB = ∠1 + ∠2
∠QCB > ∠PBC (given)
⇒ ∠1 + ∠2 > ∠1 + ∠3
⇒ ∠2 > ∠3
∴ AC > AB
(∴ In a A, side opposite to larger angle is always longer).

Question 3.
In Fig. below, ∠B < ∠A and ∠C < ∠D. Show that AD < BC.

Solution:
Given
∠B < ∠A i.e., ∠A > ∠B
∠C < ∠D i.e., ∠D> ∠C
To prove: AD > BC
i.e., BC > AD
Proof:
In ∆OCD
∠D > ∠C
OC > OD
(∴ In a ∆, sides opposite to larger angle are always longer) …(1)
In ∆OBA
∠A > AB
OB > OA
(∴ In a A, sides oppositedo larger angle are always longer) …(2)
Adding (1) and (2), we get
OC + OB > OD + OA
BC > AD

Question 4.
AB and CD are respectively the smallest and longest sides of a quadrilateral ABCD (see Fig. below). Show that ∠A > ∠C and ∠B > ∠D.
Solution:
Given
AB is the smallest siBe and CD is the longest side
To prove:

1. ∠A > ∠C and
2. ∠B > ∠D

Construction:
Join AC

1. Proof:
In, ∆ABC
BC > AB (∴ AB is the smallest side) ∠1 > ∠3
(∴ In a ∆ angle opposite to longer side is always larger) …..(1)
In ∆ACD
CD > AD (∴ CD is the largest side) ∠2 > ∠4
(∴ In a ∆ angles opposite to longer side are always larger) …(2)
Adding (1) and (2), we get
∠1 + ∠2 > ∠3 + ∠4
∠A > ∠C

2. To prove: AB > AD
Construction:
Join BD
Proof:
In ∆ABD
AD > AB (AB is the smallest side)
∠5 > ∠7 …(3)
In ∆BCD
CD > BC (CD is the longest side)

∠6 > ∠8 …(4)
Adding (3) and (4), we get
∠5 + ∠6 > ∠7 + ∠8
∠B > ∠D

Question 5.
In Fig. below, PR > PQ and PS bisects ∠QPR. Prove that ∠PSR > ∠PSQ.

Sol.
Given:
PR > PQ
∠1 = ∠2
To prove:
∠PSR > ∠PSQ
Proof:
In ∆PSQ
∠PSR = ∠1 + ∠Q (EAP)
In ∆PSR
∠PSQ = ∠2 + ∠R (EAP)
= ∠1 + ∠R (∠1 = ∠2)
In ∆PQR
PR > PQ (given)
∠Q > ∠R
(∴ In a ∆, angle opposite to longer side is always larger)
Adding ∠1 on both sides
∠Q + ∠l > ∠R + ∠1
∴ ∠PSR > ∠PSQ
(∴ ∠PSR = ∠1 + ∠Q and ∠PSQ = ∠1 + ∠R)

Question 6.
Show that of all the line segments drawn from a give point not on it, the perpendicular line segment is the shortest.
Solution:
Given
Let us consider the ∆PMN such that ∠M = 90°
Since, ∠M + ∠N + ∠P = 180° [Sum of angles of a triangle]

∠M = 90° [PM ⊥ l]
∠N < ∠M
PM < PN …..(1)
Similarly PM < PN₁ …..(2)
PM < PN₂ …..(3)
From (1), (2) and (3), we have PM is the smallest line segment drawn from P on the line l.
Thus, the perpendicular segment is the shortest line segment drawn on a line from a point not on it.

MP Board Class 9th Maths Solutions

MP Board Class 9th Maths Solutions Chapter 8 Quadrilaterals Ex 8.1

Question 1.
The angles of quadrilateral are in the ratio 3 : 5 : 9 : 13. Find all Ijbe angles of the quadrilateral.

Solution:
∠A = 3x, ∠B = 5x, ∠C = 9x, ∠D = 13x
In quadrilateral ABCD
∠A + ∠B + ∠C + ∠D = 360°
(∴ Sum of all the angles of ♢ is equal to 360°)

3x + 5x + 9x + 13x = 360°
30x = 360°
x = \(\frac{360^{\circ}}{30^{\circ}}\)
Let angle in ratio be x then angles are x= 12°
∠A = 3 x 12° = 36°
∠B = 5 x 12° = 60°
∠C = 9 x 12° = 108°
∠D = 13 x 12° = 156°

Question 2.
If the diagonals of a parallelogram are equal, then show that it is a rectangle.
Solution:
Given
ABCD is a parallelogram in which
AC =DB
To prove:
ABCD is a rectangle.
Proof
In ∆DAB and ∆CBA
DB = CA (given)
AB = BA (common)
AD = BC (∴ opposites sides of ∥^gm are equal)
∆DAB = ∆CBA (by SSS)
and so ∠DAB = ∠CBA
AD∥BC and AB is the transversal (by CPCT)
∴ ∠A + ∠B = 180° (CIA’s)
⇒ ∠A + ∠A = 180° (∴ ∠A = ∠B)
∴ ∠A = 90°
∠A = ∠C = 90°
and ∠B = ∠D = 90°
In ∥^gm ABCD, all the angles are right angles.
ABCD is a rectangle.

Question 3.
Show that if the diagonals ofa quadrilateral bisect each other at right angles, then it is a rhombus.
Solution:
Given
OA = OC, OB = OD and ∠AOD = 90°
To prove:
ABCD is a rhombus.
Proof:
In ∆AOD and ∆COB

OA = OC (given)
OD = OB (given)
∠1 = ∠2 (V.O.A.’s)
∴ ∆AOD = ∆COB (by SAS)
and so AD = CB (by CPC 7)
∠3 = ∠4 (by CPCT)
∠3 and ∠4 are A.I.A.’s and are equal
∴ AD ∥ PC (proved)
AD = BC
∴ ABCD is a parallelogram
In ∆AOD and ∆COD,
OA = OC (given)
OD = OD (common)
∠1 = ∠5 = 90°
(∴ ∠1 + ∠5 = 180° ⇒ 90° + ∠5 = 180° ∴ ∠5 = 90°)
∴ ∠AOD = ∠COD (by SAS)
and so AD = CD (by CPCT)
In ∥^gm APCD, all the sides are equal.
ABCD is rhombus.

Question 4.
Show that the diagonals of a square are equal and bisect each other at right angles.
Solution:
Given
ABCD is a square.
To prove:

1. AC = BD
2. OA = OC and OB = OD
3. ∠AOD = 90°

Proof:
In ∆DAB and ACBA,
DA = CB (given)
AB = BA (common)
∠A = ∠B (each 90°)
∴ ∆DAB = ∆CBA (by SAS)
and so BD =AC (by CPCT)

2. In ∆AOD and ∆COB, AD = CB(given)

∠4 = ∠5 (A.I.A.’s)
∠6 = ∠7 (A.I.A. ’s)
∆AOD = ∆COB (by ASA)
and so OA=OC , (byCPCT)
OD = OB (byCPCT)

3. In ∆AOD and ∆COD,
AO = CO (proved)
OD = OD (common)
AD = CD (given)
∆AOD = ∆COD (by SSS)
and so ∠1 = ∠3 (byCPCT)
∠1 + ∠3 = 180° (LPA’S)
⇒ ∠1 + ∠1 = 180° (∠1 = ∠3)
⇒ 2∠1 = 180°
∴ ∠1 = \(\frac{180^{\circ}}{2}\)

Question 5.
Show that if the diagonals of a quadrilateral are equal and bisect each other at right angles, then it is a square.
Solution:

Give
ABCD is in which
AC = BD
OA = OC
and OB = OD
∠AOD = 90°
To prove
ABCD is a square
Proof:
In ∆AOD and ∆COB,
OA = OC (given)
OD = OB (given)
∠7 = ∠8 (V.CXA.’s)
∴ ∆AOD = ∠COB
and so AD = BC
and ∠3 = ∠1 (byCPCT)
∠3 and ∠1 are A.I.A.’s and are equal
∴ AD ∥ BC
Similarly, AB ∥ CD
∴ ABCD is a parallelogram.
In ∆AOD and ∆COD,
OA = OC (given)
OD = OD (common)
∠7 = ∠9 (each 90°)
∆AOD = ∠COD (by SAS)
AD = CD (byCPCT)
In ∥^gmABCD, adjacent sidesAD = CD
∴ ABCD is a rhombus
In ∆DAB and ∆CBA,
DA = CB (proved)
AB = BA (common)
DB = CA (given)
∆DAB = ∆CBA (bySSS)
∠A = ∠B (by CPCT)
∠A + ∠B = 180° (CIA’s)
2∠A = 180°
∠A =90°
ABCD is a square.

Question 6.
Diagonals AC of a parallelogram ABCD bisects ∠A (see Fig). Show that

1. it bisects ∠C also,
2. ABCD is a rhombus.

Solution:
Given
ABCD is a parallelogram in which ∠1 = ∠2
To prove:

1. ∠3 = ∠4
2. ABCD is a rhombus.

Proof
1. ∠1 = ∠4 (A.I.A.’s) ….(i)
(∴ AD ∥ SC and AC is the transversal)
∠2 = ∠3 (A.I.A.’s) …(ii)
(∴ AB ∥ DC and AC is the transversal)
∠1 = ∠2 (given) …(iii)

From (i), (ii) and (iii), we get
∠4 = ∠3
(ii) From (ii) and (iii), we get,
∠1 = ∠3
In ∆ADC,
∠1 = ∠3
∴ AD = DC (In a A, sides opposites to equal angles are equal) and so ABCD is a rhombus
(∴ In a ∥^gm, if adjacent sides are equal then it is a rhombus)

Question 7.
ABCD is a rhombus, show that diagonal AC biusects ∠A as well as ∠C and diagonal BD biusects ∠B as well as ∠D.
Solution:
Given
ABCD is a rhombus.
To prove
∠1 = ∠2, ∠3 = ∠4, ∠5 = ∠6, ∠7 = ∠8.
Proof:
In ∆ADC and ∆ABC.

AD = AB (Adj. sides of a rhombus)
DC = BC (Adj. sides of a rhombus)
AC = AC (common)
∴ ∆ADC = ∆ABC (by SSS)
so ∠1 = ∠2 (by CPCT)
and ∠3 = ∠4 (by CPCT)
∴ AC bisects ∠A and ∠C
Similarly, ∠5 = ∠6 and ∠7 = ∠8
BD bisects ∠B and ∠D.

Question 8.
ABCD is a rectangle in which diagonal AC bisects ∠A as well as ∠C. Show that

1. ABCD is a square
2. diagonal BD bisects ∠B as well as ∠D.

Solution:
Given
ABCD is a rectangle.
∠1 = ∠2 and ∠3 = ∠4
To prove:

1. ABCD is a square
2. ∠5 = ∠6 and ∠7 = ∠8

Proof:
1. ∠A = ∠C
(∵ Rectangle is ∥^gm and in a ∥^gm opp. angles are equal.)

\(\frac{1}{2}\)∠A = \(\frac{1}{2}\)∠C
∠A = ∠C
∠2 = ∠4
In ∆ABC, ∠2 = ∠4
AB = BC
(In a A, sides opp. to equal angles are always equal)
ABCD is a rectangle in which adjacent sides are equal.
∴ ABCD is a square.

2. In ∆ABD,
AB = AD (∴ ABCD is a square)
∴ ∠5 = ∠7 (∴ In a A, angles opp. to equal sides are equal) ….(1)
AB ∥ DC and BD is the transversal
∴ ∠6 = ∠7 …(2)
AD ∥ BC and BD is the transversal.
∴ ∠5 = ∠8 …(3)
From (1) and (3), we get
∠7 = ∠8
From (1) and (2), we get
∠5 = ∠6
Diagonal BD bisects ∠B as well as ∠D.

Question 9.
In parallelogram ABCD, two points P and Q are taken on diagonal BD such that DP = BQ (see Fig.). Show that

1. ∆APD = ∆CQB
2. AP = CQ
3. ∆AQB = ∆CPD
4. AQ = CP A
5. APCQ is a parallelogram

Given
ABCD is a parallelogram.
∴ AD = BC, AB= DC and DP = BQ
To prove:

1. ∆APD = ∆CQB
2. AP = CQ
3. ∆AQB = ∆CPD
4. AQ = CP
5. APCQ is a parallelogram

Proof:
In ∆APD and ∆CQB
PD = QB (given)
AD = CB (given)
∠2 = ∠1 (AIA’s)
∆APD = ∆CQB (by SAS)
and so AP = CQ (by CPCT)

In ∆AQB and ∆CPD,
AB = CD (given)
∠3 = ∠4 (AIA’s)
BQ = DP (given)
∆AQB = ∆CPD (by SAS)
and so AQ = CP (by CPCT)
In quadrilaterals AQCP,
AP = CQ
AQ = CP
AQCP is a parallelogram.

Question 10.
ABCD is a parallelogram and AP and CQ are perpendicular from vertices A and C on diagonal BD (see Fig.). Show that

1. ∆APB = ∆CQD
2. AP = CQ

Solution:
Given
ABCD is a ∥^gm in which Ap ⊥ BD and CQ ⊥ BD.
To prove:

1. ∆APB = ∆CQD
2. AP = CQ

Proof:
In ∆APB and ∆CQD,
∠P = ∠Q (each 90°)
∠1 = ∠2 (AIA’s)
AB = CD (given)
∆APB ≅ ∆CQD (byAAS)
and so AP = CQ (by CPCT)

Question 11.
In ∆ABC and ∆DEF, AB = DE, AB ∥ DE, BC = EF and BC ∥ EE. Vertices A, B and C are joined to vertices, D,E and F respectively (see Fig.). Show that

1. quadrilateral ABED is a parallelogram
2. quadrilateral BEFC is a parallelogram
3. AD ∥ CF and AD = CF
4. quadrilateral ACFD is a parallelogram
5. AC = DF
6. ∆ABC = ∆DEF.

Solution:
Given
AB = DE and AB ∥ DE
BC = EF and BC ∥ EF
To prove

1. ABED is a ∥^gm
2. BEFC is a ∥^gm
3. AD ∥ CF and AD – CF
4. ACFD is a ∥^gm
5. AC =DF
6. ∆ABC ≅ ∆DEF

Proof:
1. AB = DE and AB ∥ DE (given)
ABED is ∥^gm
and so AD ∥ BE and AD = BE …(1)

2. BC = EF and BC ∥ FC (given)
BEFC is a ∥^gm
and so BE ∥ CF and BE = CF …..(2)

3. From (1) and (2), we get
AD ∥ CF and AD = CF

4. AD ∥ CF and AD = CF (proved)
ACFD is a ∥^gm

5. and so AC = DF
(In a parallelogram, opp. sides are equal)

6. In ∆ABC and ∆DEF,
AB = DE (given)
BC = EF (given)
AC = DF (proved)
∆ABC = ∆DEF (by SSS)

Question 12.
ABCD is a trapezium in which AB ∥ CD and AD = BC (see Fig.). Show that:

1. ∠A = ∠B
2. ∠C = ∠D
3. ∆ABC ≅ ∆BAD
4. Diagonal AC = diagonal BF)

[Hint: Extend AB and draw line through C parallel to DA intersecting AB produced at E.]
Solution:
Given
AB ∥ CD, AD = BC
To prove:

1. ∠A = ∠B
2. ∠C = ∠D
3. ∆ABC ≅ ∆BAD
4. diagonal AC = diagonal BD

Construction:
Draw a line CE ∥ DA which intersect AB produced at E.
Proof:
1. In quadrilateral ADCE,
AD ∥ EC (by const)
and AE ∥ DC ( AB ∥ DC)
∴ ADCE is a parallelogram
and so AD = EC (opp. sides of a ∥ are equal)…(i)
AD = BC (given) ….(ii)
From (i) and (ii), we get
BC = EC
In ∆BCE BC = EC (proved)
∠4 = ∠3
(∴ In a ∆, angles opp. to equal sides are equal)
∠2 + ∠3 = 180° (LPA’s) …(iii)
∠1 + ∠4 = 180° (CIA’s) …(iv)
From (iii) and (iv), we get
∠2 + ∠3 = ∠1 + ∠4
∠2 = ∠1 (∠3 = ∠4)
i.e., ∠A = ∠B

2. ∠3 = ∠5 (AIA’s) …(v)
∠6 = ∠4
(∴ ADCE is a ∥^gm and in a ∥^gm opp. angles are equal) …(vi)
∠4 = ∠3 (proved) …(vii)
From (v), (vi) and (vii), we get
∠5 = ∠6
i.e., ∠C = ∠D

3. In ∆ABC and ∆BAD,
AB = BA (common)
BC = AD (given)
∠2 = ∠1 (proved)
∆ABC ≅ ∆BAD (by SAS)
and so AC =BD (by CPCT)

4. diagonal AC = diagonal BD (proved)

Mid Point Theorem:
The line segment joining the mid-points of the sides of a triangle is parallel to the third side and equal to half of it.
Given.
ABC is a A in which D and E are the mid-points of sides AB and AC respectively.
To prove.
DE ∥ BC and DE = \(\frac{1}{2}\) BC
Construction:
Extend DE uptoFsuch that DE = EF. Join CF.
Proof:
In ∆AED and ∆CEE
AE = CE (E is the mid – point of AC)
∠AED = ∠CEF (VOA’s)
DE = FE (By constriction)
∆AED = ∆CEF , (By SAS)
and so ∠DAE = ∠FCE (By CPCT)
AD = CF (By CPCT)
∠DAE and ∠FCE are alternate interior angles and are equal.

AD ∥ FC
⇒ DB ∥ FC
Now, AD = DB and AD = FC
DB = FC
In BCFD, DB ∥ FC and DF = BC
BCFD is a ∥^gm
and so DF ∥ BC and DF = BC
⇒ DF ∥ BC and 2DF = BC
DE ∥ BC and DE = \(\frac{1}{2}\) BC

Converse of mid point theorem:
The line drawn through the mid – point of one side of a triangle and parallel to another side, bisects the third side.
Given
ABC is a A in which D is the mid-point of AB and DE ∥ BC.
To Prove:
E is the mid – point of AC.
Construction:
Mark a point F on AC and join DF.
Proof:
Let E be not the mid – point of AC. Let us assume that F be the mid – point of AC.
Then by mid-point theorem

DF ∥ BC
DE ∥ BC (Given)
From (i) and (ii), we get
DE ∥ DF
But lines DE and DF are intersecting lines, intersecting at D. This is a contradiction. So our supposition is wrong. Hence E is the mid – point of AC.

MP Board Class 9th Maths Solutions

MP Board Class 7th General English Solutions Revision Exercises 3

Read and Learn (पढ़ो और याद करो) :
Students should do themselves.

Comprehension (बोध प्रश्न):

(A) Answer These questions :
(इन प्रश्नों के उत्तर दीजिए)

Question 1.
What is the poem Lohri about ?
Answer:
The poem is about the festival of ‘Lohri’.

Question 2.
Where did the five friends go one day?
Answer:
The five friends went to the fair one day.

Question 3.
Why is the story called, “One Way Ticket” ?
Answer:
All the five friends collected their money they had and then only they were able to buy a one way ticket for the return journey.

Question 4.
Who built the buildings at Orchha ?
Answer:
Bundela kings built the buildings at Orchha.

Question 5.
What were Laxmi Bai’s last words?
Answer:
The last words of Maharani Laxmi Bai were, “Let no Britisher touch my body.”

(B) Read the following and tick true or false :
(निम्नलिखित वाक्यों को पढ़कर सत्य/असत्य पर चिन्ह लगाइए)

(i) Manu was a cowardly girl. T/F
(ii) The five friends had no money to return home. T/F
Answer:
(i) False
(ii) False

(C) Tick the correct option:
(सही विकल्प पर चिह्न लगाइए)

(i) Bonfires consume a lot of/a little wood.
Answer:
a lot of

(ii) The Bundela Kings made Orchha/Sanchi their capital.
Answer:
Orchha.

(D) Fill in the blank spaces :
(रिक्त स्थान भरिए)

(i) Lohri celebrates the harvesting of new …………..
(ii) Laxmi Bai took training in martial …………..
Answer:
(i) crop
(ii) arts.

Word Power (शब्द समर्थ):

(A) Write the homophones for :
(समान स्वर वाले शब्दों को लिखो।)
(i) hear
(ii) write
Answer:
(i) here
(ii) right.

(B) Write one work for each phrase given below:
(नीचे दिए प्रत्येक शब्द समूह के लिए एक शब्द लिखिए।)

(i) A monument built in memory of someone who died somewhere else.
(ii) Words written in memory of a person who has died; an inscription on a tombstone.
Answer:
(i) Cenotaph
(ii) epitaph.

(C) Write the meanings of the following words:
(निम्न शब्दों के अर्थ लीखिए)

(i) merge
(ii) rear
Answer:
(i) mix
(ii) to bring up.

(D) Classify the following into cenotaph and tomb:
(निम्न को स्मारक और मकबरे में वर्गीकृत कीजिए।)
(i) The Taj Mahal.
(ii) Amar Jyoti at Vijay Chowk.
(iii) Rajghat.
(iv) Humayun Ka Makbara
(v) Chhatries at Orchha
(vi) Samadhi of Laxmi Bai
Answer:
Cenotaph-Amar Jyoti at Vijay Chowk, Rajghat, Chhatries at Orchha, Chhatries at Maheswar and Indore.
Tomb – The Taj Mahal, Humayun Ka Makbara, Samadhi of Laxmibai.

Grammar in Use (व्याकरण प्रयोग):

(A) Fill in the blank spaces using ‘between’ and ‘among’:
(between और among का प्रयोग कर रिक्त स्थान भरिए)

(i) The letter S comes ……… the letter R and T of the English alphabet.
(ii) She works ………. the poor.
Answer:
(i) between
(ii) among.

(B) Combine the sentences using ‘where’ and ‘when’:
(Where और When का प्रयोग कर वाक्यों को जोड़िए।)

(i) I found the pen. I had kept it.
Answer:
I found the pen where I had kept it.

(ii) Sona called me. I was reading.
Answer:
Sona called me when I was reading.

(C) Encircle the correct adjective for the following nouns :
(निम्नलिखित संज्ञाओं के लिए सही विशेषण पर गोला लगाओ)

(D) Make more words by adding ‘ly’.
(‘ly’ लगाकर अधिक शब्द बनाइए)

(i) brave – bravely
(ii) fearless – fearlessly
(iii) extreme – extremely

(E) Punctuate the following paragraph.
(निम्न अनुच्छेद में विराम चिन्ह का प्रयोग कीजिए।)
Answer:
Once Bishni, Kishto, Gittoo and Lambu went to see a Bal mela in a school. There, they saw many Science models made by students. Bishni asked, “What is the model about ?” Kishto explained, “This is about a water pump.”

Let’s Write (आओ लिखें) :

Question 1.
Write about the Holi celebration in one paragraph.
(होली पर्व के बारे में एक अनुच्छेद लिखिए।)
Answer:
Holi is the festival of colours. The people express their happiness by throwing colours on their friends, relatives and neighbours. They make fun. They use dry and wet colours. Relating to the festival and season people are lost in singing songs. They feel happy by welcoming their friends with sweetmeats and tea or coffee or cold drink. Sugarcane fields look full of cheerfulness of the farmers who work there. Grain fields look very beautiful. Some people throw mud on one another and shout. Everyone small or big bears a smile on his face.

(ii) Write a paragraph about Orchha.
(ओरछा के बारे में एक अनुच्छेद लिखिए।)

(iii) Write five lines about the qualities of Maharani Laxmi Bai.
(महारानी लक्ष्मी बाई के गुणों के बारे में पाँच लाइनें लिखिए)
Answer:

Maharani Laxmi Bai was the queen of Jhansi. She was brave, courageous and bold from her early childhood. She was skilled in horse riding, shooting, wrestling and all the martial arts and continued to practise them even after her marriage with Gangadhar Rao, the king of Jhansi.

When Britishers declared to merge Jhansi with British empire, after her husband’s death, she opposed it and bravely fought against them not thinking that she was a woman. She was a great patriot. She tied her son to her back and led her army against the British. She fought courageously till her last breath and did not let any Britisher touch her living or dead.

Let’s Do It (आओ इसे करें):

(A) Read the given paragraph and write answers to the questions that follow :
(दिए गए अनुच्छेद को पढ़कर उसके नीचे दिए प्रश्नों के उत्तर लिखिए।)

Question 1.
Why do birds build nests?
Answer:
Birds build nests to lay their eggs which need to be kept warm.

Question 2.
Which bird makes its nest out of mud ?
Answer:
Swallows and martins make their nests out of mud.

Question 3.
What does a tailor bird do to build its nest ?
Answer:
A tailor bird sews leaves together to make its nest.

Question 4.
Which birds make their nests on the ground ? Why?
Answer:
Ostrich and Kingfisher make their nest on the ground because they cannot fly.

Question 5.
Which birds lay their eggs in other birds, nests?
Answer:
Cockoo lays its eggs in other bird’s nests.

(B) Match these words with words opposite in their meaning :
(इन शब्दों को उनके विपरीतार्थक शब्दों से मिलान कीजिए)

1. many – (a) similar
2. safe – (b) unsafe
3. strong – (c) uncomfortable
4. different – (d) few
5. comfortable – (e) weak
Answer:
1. → (d)
2. → (b)
3. → (e)
4. → (a)
5. → (c).

MP Board Class 7th English Solutions

MP Board Class 7th Science Solutions Chapter 13 Motion and Time

Motion and Time Intex Questions

Question 1.
Paheli wondered how time was measured when pendulum clocks were not available?
Answer:
Many times measuring devices were used in different parts of the world before the pendulum clocks became popular. Water clocks, sand clocks and sundials are some examples of such devices.

Question 2.
Boojho wants to know whether there is any device that measures the speed?
Answer:
Yes, speedometer.

Activities

Activity – 1
Table gives some common examples of motions. Identify the type of motion in each case?
Answer:
Some examples of different types of motion

Activity – 2
Draw a straight line on the ground with chalk powder or lime and ask one of your friends to stand 1 to 2 m away from it. Let your friend gently roll a ball along the ground in a direction perpendicular to the line. Note the time at the moment the ball crosses the line and also when it comes to rest (Fig.) How much time does the ball take to come to rest? Measure the distance between the point at which the ball crosses the line and the point where it comes to rest. You can use a scale or a measuring tape. Let different groups repeat the activity. Record the measurements in Table. In each case calculate the speed of the ball?

Answer:

Activity – 3
The unit of speed in the given table is in km/h. Change this speed in to m/s?
Answer:
Speed of some animals.

Motion and Time Text Book Exercises

Question 1.
Classify the following as motion along a straight line, circular or oscillatory motion:

1. Motion of your hands while running.
2. Motion of a horse pulling a cart on a straight road.
3. Motion of a child in a merry – go – round.
4. Motion of a child on a see – saw.
5. Motion of the hammer of an electric bell.
6. Motion of a train on a straight bridge.

Answer:

1. Oscillatory
2. Straight line
3. Circular
4. Oscillatory
5. Oscillatory
6. Straight line.

Question 2.
Which of the following are not correct?

1. The basic unit of time is second.
2. Every object moves with a constant speed.
3. Distances between two cities are measured in kilometres.
4. The time period of a given pendulum is not constant.
5. The speed of a train is expressed in m/h.

Answer:

2. Every object moves with a constant speed.
5. The speed of a train is expressed in m/h.

Question 3.
A simple pendulum takes 32 s to complete 20 oscillations?What is the time period of the pendulum?
Answer:
Given, time taken to complete 20 oscillations = 32 seconds
∴Time taken to complete 1 oscillation = \(\frac{32}{20}\)s = 1.6 s
Thus, the time period of pendulum is 1.6 s

Question 4.
The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Calculate the speed of the train?
Answer:
Given, distance between two stations = 240 km and time taken to cover this distance = 4 hour
We know that,

\(\frac{240}{4}\) = 60 km/hour.
Thus, the speed of the train is 60 km/hour.

Question 5.
The odometer of a car reads 57321.0 km when the clock shows the time 08.30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/h also?
Answer:
Given, reading of odometer at time 08:30 AM = 57321.0 km and reading of odometer at time 08:50 AM = 57336.0 km.
∴Distance covered by car = (57336.0 – 57321.0) km = 15 km and Time taken = 8.50 – 8.30 = 20 minutes
We know that,

Question 6.
The odometer of a car reads 57321.0 km when the clock shows the time 08.30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/h also?
Answer:
Given, reading of odometer at time 08:30 AM = 57321.0 km and reading of odometer at time 08:50 AM = 57336.0 km
∴Distance covered by car = (57336.0 – 57321.0) km = 15 km and Time taken = 8.50 – 8.30 = 20 minutes We know that,

Thus, the distance between Salma’s school from her house is 1800 m or 1.8 km.

Question 7.
Show the shape of the distance – time graph for the motion in the following cases:

1. A car moving with a constant speed.
2. A car parked on a side road.

Answer:

Question 8.
Which of the following relations is correct?

Answer:

Question 9.
The basic unit of speed is:
(a) 100km.
(b) m/min
(c) km/h
(d) m/s.
Answer:
(d) m/s.

Question 10.
A car moves with a speed of 40 km/h for 15 minutes and then with a speed of 60 km/h for the next 15 minutes. The total distance covered by the car is:
(a) 100 km
(b) 25 km
(c) 15 km
(d) 10 km.
Answer:
(b) 25 km.
Distance travelled in first 15 minutes = Speed x Time = 40 km/h x 15 minutes.
= 40 km/h × \(\frac{15}{60}\) hour
= 10 km
Distance travelled in last 15 minutes = Speed x Time = 60 km/h x 15 minutes
= 60 km/h × 15 minutes
= 60 km/h × \(\frac{15}{60}\) hour
= 15 km.
Total distance = (10 + 15) km = 25 km.

Question 11.
Suppose the two photographs, shown in Fig. (a) and Fig. (b) had been taken at an interval of 10 seconds. If a distance of 100 meters is shown by 1 cm in these photographs, calculate the speed of the blue car?


Answer:
Speed = \(\frac{100 km}{10 h}\) = 10 km/h.

Question 12.
Fig. shows the distance – time graph for the motion of two vehicles A and B. Which one of them is moving faster?

Answer:
Car A is moving faster.

Question 13.
Which of the following distance – time graphs shows a truck moving with speed which is not constant?

Answer:
(iii)

Motion and Time Additional Important Questions

Objective Type Questions

Question 1.
Choose the correct alternative :

Question (a)
The time taken for one oscillation is called its
(a) Pitch
(b) Frequency
(c) Vibration
(d) Time period.
Answer:
(d) Time period.

Question (b)
1 minute has?
(a) 30 second
(b) 60 second
(c) 100 second
(d) None of these.
Answer:
(b) 60 second

Question (c)
The smallest time interval that can be measured with commonly available clocks and watches is?
(a) 1 second
(b) 1 minute
(c) 1 hour
(d) None of these.
Answer:
(c) 1 hour

Question (d)
The ages of stars and planet are often expressed in –
(a) billions of years
(b) days
(c) years
(d) None of these.
Answer:
(a) billions of years

Question (e)
The distance moved by a vehicle can be measured by –
(a) speedometer
(b) odometer
(c) regulator
(d) None of these.
Answer:
(b) odometer

Question (f)
The distance – time graph of a body moving with uniform speed is –
(a) a curve
(b) a straight line
(c) line parallel to x – axis
(d) None of these.
Answer:
(b) a straight line

Question 2.
Fill in the blanks:

1. We shall use the term speed for average ……………………….
2. An object moving along a straight line with a constant speed is said to be in …………………………
3. The to and fro motion of a simple pendulum is an example of a ……………….. or ……………………. motion.
4. The basic unit of time is a ……………………….
5. The basic unit of speed is ………………………..
6. Periodic events are used for the measurement of ……………………….
7. The distance – time graph for the motion of an object moving with a constant speed is a ……………………
8. The speedometer records the speed in ……………………..
9. Odometer is used to measure ………………………
10. The distance moved by an object is a unit time is called its ………………………….

Answer:

1. Speed
2. Uniform speed
3. Periodic, oscillatory
4. Second
5. m/s
6. Time
7. Straight line
8. km/h
9. Distance
10. Speed.

Question 3.
Which of the following statements are true (T) or false(F).

1. The distance moved by objects in a given interval of time can help us to decide which one is faster or slower.
2. We shall not use the term speed for average speed.
3. The to and fro motion of a simple pendulum is an example of a periodic motion.
4. Janter Manter in Delhi and Jaipur have big Sundials.
5. In non – uniform motion, the speed of an object changes.
6. Clocks or watches are perhaps the most common time measuring devices.
7. Different units of time are used depending on the need.

Answer:

1. True
2. False
3. True
4. True
5. True
6. True
7. True.

Motion and Time Very Short Answer Type Questions

Question 1.
Define motion.
Answer:
Motion is the change in position of a body with respect to line and its surroundings.

Question 2.
What type of motion do the vehicles on a straight road perform?
Answer:
The vehicles perform rectilinear motion on the road.

Question 3.
What type of motion does the wheel of a bicycle perform?
Answer:
The wheel of a bicycle perform rotatory or circular motion.

Question 4.
What is uniform motion?
Answer:
Motion of a body along a straight line covering equal distances in equal intervals of time is called uniform motion.

Question 5.
Give two example of non – uniform motion?
Answer:

1. Motion of the train when its driver applies breaks.
2. Motion of the cricket ball when the bowler throws the ball and the ball is hit by the player.

Question 6.
Give two example of periodic motion?
Answer:

1. Rotation of earth on its axis.
2. Moon moves around the earth.

Question 7.
What is oscillatory motion?
Answer:
The to and fro motion is called periodic or an oscillatory motion.

Question 8.
An object is hung from a spring is pulled down and left? What type of motion does the object perform?
Answer:
The object perform oscillatory motion which is also a periodic motion.

Question 9.
Write the formula for speed?
Answer:

Question 10.
What is the unit of speed?
Answer:
Unit of speed is meter per second.

Question 11.
A snail covers a distance of 1 meter in 10 sec. What is the speed of the snail?
Answer:
image
= 0.1 ms^-1
= 0.1 m per sec.

Question 12.
What happens to the speed of your bicycle when you pedal faster?
Answer:
On pedalling fast the speed of bicycle increase.

Question 13.
“Speed of a car is 8 km/h”. What does it mean?
Answer:
When we say that a car is moving with a speed of 80 kilometer per hour, it implies that it will cover a distance of 80 kilometre in one hour.

Question 14.
Define a day?
Answer:
The time between one sunrise and the next is called a day.

Question 15.
What is month ?
Answer:
A month is measured from one new moon to the next.

Question 16.
What is year?
Answer:
A year is fixed as the time taken by the earth to complete one revolution of the sun.

Question 17.
What is bob?
Answer:
The metallic ball is called bob of the pendulum.

Question 18.
What is the use of stop – watch?
Answer:
Stop – watch is used to measure exact time in case of atheletic events as it can be stopped and started any moment.

Question 19.
When you travel in bus or car then, generally, what kind of motion it is?
Answer:
Linear motion.

Question 20.
There is 100 metres line on which two sprinters have to run, when they run, what kind of motion it will be?
Answer:
Linear motion.

Question 21.
See the picture and tell whose speed is more:


Answer:
Speed of tiger is more than the speed of horse.

Motion and Time Short Answer Type Questions

Question 1.
Define periodic motion?
Answer:
Periodic motion:
The motion of a body which is repeated at regular intervals of time is called periodic motion. In periodic motion, a body covers equal distances in equal intervals of time; e.g. revolution of earth round the sun, the motion of moon round the earth, the motion of a swing, the motion of a pendulum, etc.

Question 2.
Define non – periodic motion?
Answer:
Non – periodic motion:
The motion of a body which is not repeated at regular intervals of time is called non – periodic motion. In non – periodic motion, a body does not cover equal distances in equal intervals of time; e.g. an athelete running on a track, a moving car on busy road, etc.

Question 3.
Define oscillatory motion?
Answer:
Oscillatory motion:
A body is said to be in oscillatory motion when it moves to and fro about a fixed point; e.g. the pendulum of a wall clock (Fig.), a swing, a wire of sitar when plucked, striking of drum, etc. Mostly the hanging objects show oscillatory motion.

Question 4.
How can we make a pendulum of air one? What is the time – period of a pendulum?
Answer:
We can make a pendulum by suspending a metal ball with a cotton thread. The other end of the thread can be tied to same support. The time taken by a pendulum to complete its to and from movement i.e., one oscillation is called the time period of the pendulum.

Question 5.
One student reaches school in 1 hour by travelling a distance of 8 km from his house by a cycle and the other student reaches school in one and half hours by travelling a distance of 12 kms from his house by cycle. Tell whose speed was slow?
Answer:

From above calculations it is clear that the speed of both the students is same.

Question 6.
What are quartz clocks? Give a diagram of digital clock?
Answer:
Now a days most clocks or watches have an electric circuit with one or more cells. These clocks are called quartz clocks. The time measured by quartz clocks is much more accurate than that by the clocks available earlier.

Question 7.
Mark x – axis, y – axis, origin on a graph paper?
Answer:

Motion and Time Long Answer Type Questions

Question 1.
Write briefly about the development of pendulum clock?
Answer:
There is an interesting story about the discovery that the time period of a given pendulum is constant. You might have heard the name of famous scientist Galileo Galilie (A.D. 1564 – 1642). It is said that once Galileo was sitting in a church. He noticed that a lamp suspended from the ceiling with a chain was moving slowly from one side to the other.

He was surprised to find that his pulse beat the same number of times during the interval in which the lamp completed one oscillation. Galileo experimented with various pendulums to verify his observation. He found that a pendulum of a given length takes always the same time to complete one oscillation. This observation led to the development of pendulum clocks. Winding clocks and wristwatches were refinements of the pendulum clocks.

Question 2.
Discuss in details about the different range to measure time interval?
Or
Discuss the different units for measuring time interval?
Answer:
The smallest time interval that can be measured with commonly available clocks and watches is one second. However, now special clocks are available that can measure time intervals smaller than a second. Some of these clocks can measure time intervals as small as one millionth or even one billionth of a second. We might have heard the terms like microsecond and nanosecond. One microsecond is one millionth of a second. A nanosecond is one billionth of a second.

Clocks that measure such small time intervals are used for scientific research. The time measuring devices used in sports can measure time intervals that are one tenth or one hundredth of a second. On the other hand, times of historical everts are stated in terms of centuries or millenniums. The ages of stars and planet are often expressed in billions of years.

Question 3.
Draw a bar graph to show the runs scored by a team in each over?

Answer:

Question 4.
Draw a pie chart to show the composition of air?
Answer:

Question 5.
Write down the steps to make a distance – time graph?
Answer:
We can make the graph by following steps:
Step 1.
Draw two perpendicular lines to represent the two axes and mark them as OX and OY as shown in figure.

Steps 2.
Decide the quantity to be shown along the x – axis and that to be shown along the y – axis. In this case we show the time along the x – axis and the distance along the y – axis.

Steps 3.
Choose a scale to represent the distance and another to represent the time on the graph. For the motion of the car scales could be
Time : 1 min = 1 cm
Distance : 1 km = 1 cm

Step 4.
Mark values for the time and the distance on the respective axes according to the scale chosen. For the motion of the cat let mark the time 1 min, 2 min,..,on the origin x – axis from the origin Similarly, mark the distance 1 km. 2 km… on the y – axis.

Steps 5.
Now you have to mark the points on the graph paper to represent each set of values for distance and time.

Step 6.
Join all the points on the graph as shown in figure. It is a straight line. This is the distance-time graph for the motion of the car.
Note:
If the distance – time graph is a straight line, it indicates that the object is moving with a constant speed. However, if the speed of the object keeps changing, the graph can be of any shape.

MP Board Class 7th Science Solutions

MP Board Class 9th Science Solutions Chapter 14 Natural Resources

Natural Resources Intext Questions

Natural Resources Intext Questions Page No. 193

Question 1.
How is our atmosphere different from the atmospheres on Venus and Mars?
Answer:
Earth’s atmosphere has mixture of nitrogen (79%), oxygen (20%), and a small fraction of carbon dioxide, water vapours and other gases which makes the existence of life possible on Earth while the atmospheres on Venus and Mars mainly has carbon dioxide. Approximately, 95% to 97% is carbon dioxide is present on these planets which do not support existence of life.

Question 2.
How does the atmosphere act as a blanket?
Answer:
Atmosphere is a mixture of various gases along with vapour and submerged particles. It surrounds the earth and separates it from outer space. As a blanket stop interaction between body covered inside and atmosphere outside, in similar way atmosphere stops interaction between earth and space.
The most important isolations done by atmosphere are:

1. It keeps the average temperature of the Earth fairly constant during day time and even during the course of whole year.
2. It prevents a sudden increase in the temperature during day time.
3. It slows down the escape of heat from the surface of the Earth into outer space during night time.

Question 3.
What causes winds?
Answer:
Atmospheric pressure and temperature difference generates wind. As earth surface is not similar everywhere even at some places it is occupied by huge water bodies, lava emitting volcanoes, moist forest etc., a difference in temperature and pressure arises and to maintain equilibrium wave of pressure moves which we feel or notice as wind.

Question 4.
How are clouds formed?
Answer:
During day time, a large amount of water evaporates from various water bodies and of earth surface and through biological activities such as transpiration and respiration and mix up into the air. This causes the air in the atmosphere to heat up and since air is a bad conductor of heat, when this heated air rises, it expands and cools, which results in the condensation and formation of water droplets. The presence of dust and other suspended particles in air also facilitates cloud formation. The gathering of water droplets leads to the formation of clouds.

Question 5.
List any three human activities that you think would lead to air pollution.
Answer:
Three human activities leading to air pollution are:

1. Smoke from industrial and manufacturing activities etc.
2. Burning of fossil fuels for household and commercial purpose.
3. Spreading farming chemicals such as crop dusting, insect / pest killers, fertilizer dust etc.

Natural Resources Intext Questions Page No. 194

Question 1.
Why do organisms need water?
Answer:
Water is the major component of living organism some of the living organism has up to 90% of water of their body weight. Water is a wonderful liquid, it helps in performing most of the functions of our body like digestion, cell sap and oilier content formation, transportation of substance from one place to another inside the body etc.

Question 2.
What is the major source of fresh water in the city’town/ village where you live?
Answer:
The major source of fresh water near me is river.

Question 3.
Do you know of any activity which may be polluting this water source?
Answer:
Dumps from industrial activities, household works for various purpose in the fresh water sources are main activities which causes pollution. Air pollution which generates acid rain and spread submerged dust is also responsible for polluting water resources.

Natural Resources Intext Questions Page No. 196

Question 1.
How is soil formed?
Answer:
The process of soil formation is termed ‘paedogenesis’. Soil is formed mainly by the weathering of rocks through various physical chemical and biological processes with the help of various factors such as the sun, water, wind, and living organisms. It is made up of mineral particles, organic materials, air, water and living organisms. During day time, the rocks are heated up by solar rays. This causes the rocks to expand. During night time, these rocks cool down and contracts. It causes weathering of rock and formation of soil.

1. Water: It helps in breaking of rocks in two ways:
   • It goes into the cracks and crevices formed in the rocks. When this water freezes, its volume increases. As a result, the size of the cracks also increases. This helps in the weathering of rocks.
   • Water moving at fast speed carries big and small particles of rock downstream. These rocks rub against each other, resulting in breaking down of rocks. These smaller particles are carried away by running water and deposited down its path.
2. Wind: Strong winds carry away rocks, which causes rubbing of rocks. This results in the breaking down of rocks into smaller and smaller particles.
3. Living Organism: Some living organisms like lichens help in the formation of soil. Lichens grow on rock surfaces and converts them into powdery form and make soil layer. In the same way, the plants like moss also helps in the making of fine soil particles.

Question 2.
What is soil erosion?
Answer:
The blowing away or washing away of land surface by wind or water is known as soil erosion.

Question 3.
What are the methods of preventing or reducing soil erosion?
Answer:
The methods of preventing or reducing soil erosion are:

1. Plantation of tress and plants.
2. Prevention of deforestation.
3. Prevent excessive grazing.

Natural Resources Intext Questions Page No. 201

Question 1.
What are the different states in which water is found during the water cycle?
Answer:
Water is found in three different states during the water cycle:

1. Solid (snow, ice).
2. Liquid water (ground water, river water, etc.)
3. Gaseous state (water vapours).

Question 2.
Name two biologically important compounds that contain both oxygen and nitrogen.
Answer:
Two biologically important compounds that contain both oxygen and nitrogen are:

1. Amino acids.
2. Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA).

Question 3.
List any three human activities which would lead to an increase in the carbon dioxide content of air.
Answer:
Three Human activities are:

1. Burning of fuels in various processes like heating, cooking, transportation and industry.
2. Human induced forest fires.
3. The process of deforestation includes the cutting down of trees. This decreases the uptake of carbon dioxide for photosynthesis. Eventually, the content of carbon dioxide increases.

Question 4.
What is the greenhouse effect?
Answer:
Some gases like carbon dioxide, methane, nitrous oxide prevent the escape of heat from the Earth’s surface by trapping it. This increases the average temperature of the Earth. This is called the green house effect.

Question 5.
What are the two forms of oxygen found in the atmosphere?
Answer:
The two forms of oxygen found in the atmosphere are:

1. Diatomic molecular form with chemical formula O₂.
2. Triatomic molecular form with chemical formula O₃ known as ozone.

Natural Resources NCERT Textbook Exercise

Question 1.
Why is the atmosphere essential for life?
Answer:
The atmosphere is essential for life because it maintains an appropriate climate for the sustenance of life by carrying out the following activities:

1. Atmosphere keeps the average temperature of the earth fairly constant during day time.
2. It prevents a sudden increase in temperature during day time.
3. It also slows down the escape of heat from the surface of the earth into outer space during night time.

Question 2.
Why is water essential for life?
Answer:
Water is essential for life because of the following reasons:

1. Most biological reactions occur when substances are dissolved in water. Thus, all cellular processes need water as a medium to take place.
2. Transportation of biological substances needs water as a medium.

Question 3.
How are living organisms dependent on the soil?
Or
Are organisms that live in water totally independent of soil as a resource?
Answer:
Almost all living organisms are dependent on soil. Some depends directly, while some depends indirectly. Plants need soil for getting support as well as nutrients to prepare their food. On the other hand, organisms depend on plants for food and other substances that are essential for life. Herbivores depend directly upon plants and carnivores depend upon animals, which in turn depend upon plants for food. This makes them depend on soil indirectly.

Organisms that live in water are not totally independent of soil as a resource. These organisms depend on aquatic plants for food and other substances. These aquatic plants in turn require minerals for their sustenance. These minerals are carried to water bodies from soil by rivers, rain water etc. Without the supply of minerals from the soil to the water bodies, it is impossible to imagine aquatic life.

Question 4.
You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather?
Answer:
The meteorological department of the government collects data on the elements of weather such as maximum and minimum temperatures, maximum and minimum humidity, rainfall, wind speed etc. They are able to study these elements using various instruments. The maximum and minimum temperature of a day is measured by a thermometer known as the maximum – minimum thermometer. Rain fall is measured by an instrument known as the rain gauge. Wind speed is measured by anemometers. There are various instruments used to measure humidity.

Question 5.
We know that many human activities lead to increasing levels of pollution of the air, water-bodies and soil. Do you think that isolating these activities to specific and limited areas would help in reducing pollution?
Answer:
Yes. Isolating human activities to specific areas would help in reducing levels of pollution. For example, setting up of industries in isolated regions will control pollution to some extent. The pollution caused by these industries will not contaminate water resources, agriculture land, fertile land, etc.

Question 6.
Write a note on how forests influence the quality of our air, soil and water resources.
Answer:
Forests influence the quality of our air, soil, and water resources in various ways. Some of them are:

1. Forests balance the percentages of carbon dioxide and oxygen in the atmosphere. The increasing amount of carbon dioxide caused by human activities is balanced by a larger intake of carbon dioxide by plants during
   the process of photosynthesis. Simultaneously, a large amount of oxygen is released.
2. Forests prevent soil erosion. Roots of plants bind the soil tightly in a way that the surface of the soil cannot be eroded away by wind, water etc.
3. Forests help in the replenishment of water resources. During the process of transpiration, a huge amount of water vapour goes into the air and condenses to form clouds. These clouds cause rainfall that recharge water bodies.

Natural Resources Additional Questions

Natural Resources Multiple Choice Questions

Question 1.
The atmosphere of the earth is heated by radiations which are mainly ___________ .
(a) radiated by the sun
(b) re – radiated by land
(c) re – radiated by water
(d) re – radiated by land and water.
Answer:
(d) re – radiated by land and water.

Question 2.
If there were no atmosphere around the earth, the temperature of the earth will ___________ .
(a) increase.
(b) go on decreasing.
(c) increase during day and decrease during night.
(d) be unaffected.
Answer:
(c) increase during day and decrease during night.

Question 3.
What would happen, if all the oxygen present in the environment is converted to ozone?
(a) We will be protected more.
(b) It will become poisonous and kill living forms.
(c) Ozone is not stable, hence it will be toxic.
(d) It will help harmful sun radiations to reach earth and damage many life forms.
Answer:
(b) It will become poisonous and kill living forms.

Question 4.
One of the following factors does not lead to soil formation in nature ___________ .
(a) the sun
(b) water
(c) wind
(d) polythene bags.
Answer:
(d) polythene bags.

Question 5.
The two forms of oxygen found in the atmosphere are ___________ .
(a) water and ozone
(b) water and oxygen
(c) ozone and oxygen
(d) water and carbon – dioxide.
Answer:
(c) ozone and oxygen

Question 6.
The process of nitrogen – fixation by bacteria does not take place in the presence of ___________ .
(a) molecular form of hydrogen
(b) elemental form of oxygen
(c) water
(d) elemental form of nitrogen.
Answer:
(b) elemental form of oxygen

Question 7.
Rainfall patterns depend on ___________ .
(a) the underground water table.
(b) the number of water bodies in an area.
(c) the density pattern of human population in an area.
(d) the prevailing season in an area.
Answer:
(b) the number of water bodies in an area.

Question 8.
Among the given options, which one is not correct for the use of large amount of fertilisers and pesticides?
(a) They are eco – friendly.
(,b) They turn the fields barren after sometime.
(c) They adversely affect the useful component from the soil.
(d) They destroy the soil fertility.
Answer:
(a) They are eco – friendly.

Question 9.
The nitrogen molecules present in air can be converted into nitrates and nitrites by ___________ .
(a) a biological process of nitrogen fixing bacteria present in soil.
(b) a biological process of carbon fixing factor present in soil.
(c) any of the industries manufacturing nitrogenous compounds.
(d) the plants used as cereal crops in field.
Answer:
(a) a biological process of nitrogen fixing bacteria present in soil.

Question 10.
One of the following processes is not a step involved in the water – cycle operating in nature ___________ .
(a) evaporation
(b) transpiration
(c) precipitation
(d) photosynthesis.
Answer:
(d) photosynthesis.

Question 11.
The term “water – pollution” can be defined in several ways. Which of the following statements does not give the correct definition?
(a) The addition of undesirable substances to water – bodies.
(b) The removal of desirable substances from water – bodies.
(c) A change in pressure of the water bodies.
(d) A change in temperature of the water bodies.
Answer:
(c) A change in pressure of the water bodies.

Question 12.
Which of the following is not a green house gas?
(a) Methane
(b) Carbon dioxide
(c) Carbon monoxide
(d) Ammonia.
Answer:
(d) Ammonia.

Question 13.
Which step is not involved in the carbon – cycle?
(a) Photosynthesis
(b) Transpiration
(c) Respiration
(d) Burning of fossil fuels.
Answer:
(b) Transpiration

Question 14.
‘Ozone – hole’ means
(a) a large sized hole in the ozone layer.
(b) thinning of the ozone layer.
(c) small holes scattered in the ozone layer.
(d) thickening of ozone in the ozone layer.
Answer:
(b) thinning of the ozone layer.

Question 15.
Ozone – layer is getting depleted because of ___________ .
(a) excessive use of automobiles.
(b) excessive formation of industrial units.
(c) excessive use of man – made compounds containing both fluorine and chlorine.
(d) excessive deforestation.
Answer:
(c) excessive use of man – made compounds containing both fluorine and chlorine.

Question 16.
Which of the following is a recently originated problem of environment?
(a) Ozone layer depletion.
(b) Green house effect.
(c) Global warming.
(d) All of the above.
Answer:
(d) All of the above.

Question 17.
When we breathe in air, nitrogen also goes inside along with oxygen. What is the fete of this nitrogen?
(a) It moves along with oxygen into the cells.
(b) It comes out with the CO₂ during exhalation.
(c) It is absorbed only by the nasal cells.
(d) Nitrogen concentration is already more in the cells so it is not at all absorbed.
Answer:
(b) It comes out with the CO₂ during exhalation.

Question 18.
Top – soil contains the following ___________ .
(a) Humus and living organisms only.
(b) Humus and soil particles only.
(c) Humus, living organisms and plants.
(d) Humus, living organisms and soil particles.
Answer:
(d) Humus, living organisms and soil particles.

Question 19.
Choose the correct sequences ___________ .
(a) CO₂ in atmosphere → decomposers → organic carbon in animals → organic carbon in plants.
(b) CO₂  in atmosphere → organic carbon in plants → organic carbon in animals → inorganic carbon in soil.
(c) Inorganic carbonates in water → organic carbon in plants → organic carbon in animals → scavengers.
(d) Organic carbon in animals → decomposers → CO₂ in atmosphere → organic carbon in plants.
Answer:
(b) CO₂  in atmosphere → organic carbon in plants → organic carbon in animals → inorganic carbon in soil.

Question 20.
Major source of mineral in soil is the ___________ .
(a) parent rock from which soil is formed.
(b) plants.
(c) animals
(d) bacteria.
Answer:
(a) parent rock from which soil is formed.

Natural Resources Very Short Answer Type Questions

Question 1.
Name the factor responsible for rainfall patterns in India.
Answer:
North – East or South – West Monsoons.

Question 2.
Name any two organisms. Which play important role in nitrogen – fixation.
Answer:
Rhizobium and Nitrosomonas.

Question 3.
State the process and the form by which carbon enters in the living system.
Answer:
Respiration.

Question 4.
Write any one difference between oxygen and ozone.
Answer:
Oxygen is diatomic (O₂) whereas ozone is triatomic (O₃).

Question 5.
What is the temperature range on the surface of moon?
Answer:
-190°C to 110°C.

Natural Resources Short Answer Type Questions

Question 1.
Rivers from land, add minerals to sea water. Discuss, how?
Answer:
Water is wonderful solvent. As water flows over the rocks which containing soluble minerals and these mineral get dissolved in the water. Thus, Rivers from land, add minerals to sea water.

Question 2.
How can we prevent the loss of top soil?
Answer:
Loss of top soil can be prevented by stopping the falling of trees and excessive grazing by animals, growing more the vegetation cover.

Question 3.
How is the life of organisms living in water affected when water gets polluted?
Answer:
When water gets polluted, oxygen does not dissolves in water properly, which effects the aquatic organisms adversely. Also, due to undesirable chemicals and waste discharge from factories and households cause diseases to the aquatic organisms.

Question 4.
During summer, if you go near the lake, you feel relief from the heat, why?
Answer:
Due to evaporation of water, air nearby water bodies become cooler.

Question 5.
In coastal area, wind current moves from the sea towards the land during day; but during night it moves from land to the sea. Discuss the reason.
Answer:
Air above the land gets heated quickly during day and starts rising. This creates a region of low pressure as a result air over sea rushes into this area of low pressure. This movement of air from one region to the other creates winds. During night, as water cools down slowly, the air above water is warmer than the air on land. So, air moves from land to sea creating winds.

Question 6.
Following are a few organisms: (a) lichen (b) mosses (c) mango tree (d) cactus.
Which among the above can grow on stones; and also help in formation of soil? Write the mode of their action for making soil.
Answer:
Lichens and Mosses: (a) and (b).
Lichens and mosses release materials which break down the stones causes formation of soil.

Question 7.
Soil formation is done by both abiotic and biotic factors. List the names of these factors by classifying them as abiotic and biotic?
Answer:

1. Sun, water and wind are abiotic factors that forms soil.
2. Lichens, mosses and trees are biotic factors which form soil.

Question 8.
All the living organisms are basically made up of C, N, S, P, H and O. How do they enter the living forms? Discuss.
Answer:
In 1952, Stanley Miller along with Harold C. Urey designed an experiment to see how complex organic molecules might have formed under the conditions of early Earth. From long experimental method he developed organic matter from non living things. And, concluded that on specific environmental conditions non living things grow up to living form.

Question 9.
Why does the percentage of gases like oxygen, nitrogen and carbon dioxide remain almost the same in the atmosphere?
Answer:
The percentage of gases like oxygen, nitrogen and carbon dioxide remain almost the same in the atmosphere because cycling of these gases maintains consistency.

Question 10.
Why does moon have very cold and very hot temperature variations e.g., from -190°C to 110°C even though it is at the same distance from the sun as the earth is?
Answer:
No atmosphere exists on the moon thus, moon have very cold and very hot temperature variations e.g., from -190°C to 110°C even though it is at the same distance from the sun as the earth.

Question 11.
Why do people love to fly kites near the seashore?
Answer:
People love to fly kites near the seashore because air gets heated quickly during day and creates wind, which helps them to fly kites easily.

Question 12.
Why does Mathura refinery pose problems to the Taj Mahal?
Answer:
Polluted environment of Mathura due to refinery and other infrastructural facilities, industries etc. release toxic gases (like oxides of sulphur) which causes acid rain and corrode the marbles of Taj Mahal.

Question 13.
Why does water need conservation even though large oceans surround the land masses?
Answer:
Marine water is not useful for human and plant life directly. Hence fresh water need conservation. Uneven distribution of limited fresh water resources need conservation to ft ever rising demands.

Question 14.
There is mass mortality of fishes in a pond. What ma) the reasons?
Answer:

1. Thermal pollution
2. Addition of poisonous (mercury) compounds in water
3. Due to blockage of gills with any pollutant.

Natural Resources Long Answer Type Questions

Question 1.
How do fossil fuels cause air pollution?
Answer:
Most of air pollution of our environment is caused by the burning of fossil fuels, such as coal, oil natural gas and gasoline to produce electricity and power out vehicles. Carbon dioxide (CO₂) is a good indicator of how much fossil fuel is burnt and how much of other pollutants are emitted as a result. When fossil fuels are burnt, they release primarily nitrogen oxides into the atmosphere, which leads to the formation of smog and simultaneously acid rain.

The most common nitrogen – related compounds emitted into the air by human activities are collectively referred to as nitrogen oxides. Ammonia is also a harmful nitrogen compound emitted to the air, agricultural activities also contribute in air pollution but fossil fuels are most common reason for its increase day by day.

Question 2.
What are the causes of water pollution? Discuss how you can contribute in reducing water pollution.
Answer:
Domestic and industrial waste dump to water – bodies are main reason of water pollution. Industries produce huge amount of waste which contains toxic chemicals and pollutants which can cause air pollution and damage us and our environment. They contain pollutants such as lead, mercury, sulphur, asbestos, nitrates and many harmful chemicals.

Prevention of water pollution:
Stop dumping waste in water – bodies is the only way to get clear water resources. Do not throw chemicals, oils, paints and medicines down the sink drain or the toilet. If you use chemicals and pesticides for your gardens and farms, be mindful not to overuse pesticides and fertilizers. This will reduce run offs of the chemical into nearby water sources.

Natural Resources Higher Order Thinking Skills (HOTS)

Question 1.
If decomposers are removed completely from the Earth, what will be the result? Give reasons.
Answer:
Decomposers are the organisms that feed on dead and decaying matter present on the Earth. These organisms decompose the dead plants and animals returning the complex nutrients present in them in available form to the nature.

Question 2.
Why is nitrogen – fixing bacteria found only in the roots of leguminous plants?
Answer:
The roots of leguminous plants contains root nodules. These nodules provide shelter to nitrogen fixing bacteria like Rhizobium.

Natural Resources Value Based Questions

Question 1.
Manisha lived near industrial area in Delhi. During winters . she saw that the smoke has reduced the visibility in the area. Manisha requested the industries to fit in chimney the precipitators that would not release smoke particulates in air.

1. What is smog?
2. Name two disease caused due to air pollution.
3. What values are displayed by Manisha?

Answer:

1. When smoke is added to fog, smog is formed.
2. Air – pollution causes respiratory problem and allergies.
3. Manisha showed the value of self-awareness, and responsible behaviour.

Question 2.
Radha saw a child sleeping in a car parked with closed doors and glass rolled up in the open area on a sunny day near the market. She immediately raised an alarm and with the help of police, she got the window glass rolled down.

1. Why was it not safe to keep the doors with window glass rolled Up for a child inside the car?
2. Name two gases that can lead to above effect.
3. What values are exhibited by Radha?

Answer:

1. It was not safe for the child in the car with locked doors and window rolled up, the sunlight would result in the green house effect in the car. This would increase the temperature in the car and also result in the increase in CO₂ level which would lead to suffocation.
2. Carbon dioxide gas and methane gas can lead to green house effect.
3. Radha displayed the value of aware citizen and responsible behaviour.

MP Board Class 9th Science Solutions

MP Board Class 6th General English Solutions Revision Exercises 2

Listen and Write
(सुनो और लिखो)

Do yourself (स्वयं करें)

Word Power
(शब्द सामर्थ्य)

1. Make sentences using these words.
(इन शब्दों को प्रयोग कर वाक्य बनाइए।)
Answer:

1. Arrow – He pointed his arrow towards him.
2. Successful – Sohan is a successful businessman.
3. Prince – The prince was playing in the garden.
4. Confident – Gita was confident that she would win.
5. Ready – He is always ready to do work.

2. Match the animals with their young ones.
(जानवरों को उनके शिशुओं से मिलान करो।)

Answer:
1. → (e)
2. → (f)
3. → (a)
4. → (b)
5. → (c)
6. → (d)

3. Write down the five names of indoor games and outdoor games each.
(घर के अन्दर खेले जाने वाले और बाहर खेले जाने वाले पाँच खेलों के नाम बताओ।)
Answer:
Indoor games :

1. carom
2. Chess
3. Ludo
4. table tennis
5. badminton

Outdoor games :

1. football
2. kabbadi
3. hockey
4. cricket
5. kho-kho

4. Rearrange the letters to make the correct spelling of words.
(नामों की स्पैलिंग सही करने के लिए अक्षरों को पुनः व्यवस्थित करें।)
Answer:
rleevlart – traveller
badinmont – badminton
teplahne – elephant
noil – lion
roarw – arrow

Comprehension Questions
(बोध प्रश्न)

Answer these Question:
(इन प्रश्नों के उत्तर दीजिए:)

Question 1.
What lights the traveller?
Answer:
The bright and tiny spark of the star lights the traveller.

Question 2.
What different skills did Guru Dron teach the princes?
Answer:
Guru Dron taught to use different arms, to ride horses and to fight the enemy well.

Question 3.
What do you think helped Meena?
Answer:
Meena’s self confidence helped her to win the race.

Question 4.
What can the elephant do with its trunk?
Answer:
The elephant can pull down a house and pick up a pin with its trunk.

Grammar in Use
(व्याकरण प्रयोग)

1. Fill in the blanks using singular/plural form.
(एकवचन/बहुवचन से खाली स्थान भरें।)
Answer:
Singular      Plural
knife           knives
bush           bushes
fairy            fairies
man            men
key             keys
child           children
foot            feet
mouse        mice
tooth          teeth
deer           deer

2. Match the correct forms.
(सही forms का मिलान करों)
Answer:
I’m – I am               don’t – do not
I’ve – I have           won’t – would not
I’ll – I will               can’t – cannot
You’ll – you will     that’s – that is
It’s – It is                what’s – what is
It’ll – It will             who’s – who is

3. Rewrite the sentences using () and (” “).
(कोमा (.) व इनवर्टैड कोमा (” “)का प्रयोग कर वाक्यों को पुनः लिखिए।)
Example:
Mala says that she wants to be a doctor.
Mala says, “I want to be a doctor”.

Question 1.
Meena says that she wants to be an engineer.
Answer:
Meena saya, “I wan to be an engineer.”

Question 2.
Gautam says that he wants to be a teacher.
Answer:
Gautam says, “I want to be a teacher.”

Question 3.
Ravi says that he wants to be an inspector.
Answer:
Ravi says, “I want to be an inspector.”

Question 4.
Radha says that she wants to be a pilot.
Answer:
Radha says, “I want to be a pilot.”.

Question 5.
Arif says that he wants to be a lawyer.
Answer:
Arif says, “I want to be a lawyer.”

Let’s Write
(आओ लिखें)

Write five sentences about an elephant using the given clues.
(दिये गये संकेतों की सहायता से एक हाथी के बारे में 5 वाक्य लिखिए।)
Example: Huge – An elephant is a huge animal.
Answer:

1. Trunk – An elephant can pick up a pin with its trunk.
2. Tusks – An elephant has two white tusks.
3. Strong – An elephant is a strong animal.
4. Heavy load – An elephant can carry heavy load.
5. Ride – Children take a ride on elephant’s back.

MP Board Class 6 English Solutions

MP Board Class 9th Science Solutions Chapter 6 Tissues

Tissues Intext Questions

Tissues Intext Questions Page No. 69

Question 1.
What is a tissue?
Answer:
A group of cells that are similar in structure and / or work together to achieve a particular function form a tissue.

Question 2.
What is the utility of tissues in multi – cellular organisms?
Answer:
In multi – cellular organisms, different types of tissues perform different functions. Since a particular group of cells carry out only a particular function, they do it very efficiently. So, multi – cellular organisms possess a specific division of labour.

Tissues Intext Questions Page No. 74

Question 1.
Name types of simple tissues.
Answer:

1. Parenchyma
2. Collenchyma and
3. Sclerenchyma

Question 2.
Where is apical meristem found?
Answer:
At root tip and shoot tip.

Question 3.
Which tissue makes up the husk of coconut?
Answer:
Sclerenchymatous tissue.

Question 4.
What are the constituents of phloem?
Answer:
Phloem is made up of four types of elements: Sieve tubes, companion cells, phloem fibres and the phloem parenchyma.

Tissues Intext Questions Page No. 78

Question 1.
Name the tissue responsible for movement in our body.
Answer:
Muscular, tissue.

Question 2.
What does a neuron look like?
Answer:
A neuron is the unit of nervous tissue. It is elongated in shape and consists of three parts viz., dendrites, cell body and axon.

Question 3.
Give three features of cardiac muscles.
Answer:

1. Cardiac muscle cells are cylindrical, branched and uninucleate.
2. They show rhythmic contraction and relaxation throughout life.
3. They are involuntary muscles.

Question 4.
What are the functions of areolar tissue?
Answer:
Areolar tissue fills space inside the organs, supports internal organs and helps in repair of the tissues.

Tissues NCERT Textbook Exercises

Question 1.
Define the term ‘tissue’.
Answer:
The group of cells similar in structure that work together to achieve a particular function forms a tissue. This group of cells has a common origin.

Question 2.
How many types of elements together make up the xylem tissue? Name them.
Answer:
Xylem is formed of four types of elements.
They are:

1. tracheids
2. vessels
3. xylem parenchyma
4. xylem fibre.

Question 3.
How are simple tissues different from complex tissues in plants?
Answer:
Simple tissues are made of one type of cells which coordinate to perform a common function.
Complex tissues are made of more than one type of cells. All these coordinate to perform a common function.

Question 4.
Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of their cell wall.
Answer:

Question 5.
What are the functions of the stomata?
Answer:
Functions of stomata:

1. Exchange of gases, particularly CO₂ and O₂ with atmosphere.
2. Loss of water in the form of vapours during transpiration.

Question 6.
Diagrammatically show the difference between the three types of muscle fibres.
Answer:

Question 7.
What is the specific function of the cardiac muscle?
Answer:
The specific function of cardiac muscle is to contract and relax rhythmically throughout life.

Question 8.
Differentiate between striated, unstriated and cardiac muscles on the basis of their structure and site / location in the body.
Answer:

Question 9.
Draw a labelled diagram of a neuron.
Answer:

Question 10.
Name the following:

1. Tissue that forms the inner lining of our mouth.
2. Tissue that connects muscle to bone in humans.
3. Tissue that transports food in plants.
4. Tissue that stores fat in our body.
5. Connective tissue with a fluid matrix.
6. Tissue present in the brain.

Answer:

1. Squamous epithelium.
2. Tendons.
3. Phloem.
4. Adipose tissue.
5. Blood.
6. Nervous tissue.

Question 11.
Identify the type of tissue in the following: skin, bark of tree, bone, lining of kidney tubule, vascular bundle.
Answer:

1. Skin: Striated squamous epithelium
2. Bark of tree: Cork (protective tissue)
3. Bone: Connective tissue
4. Lining of kidney tubule: Cuboidal epithelium tissue
5. Vascular bundle: Conducting tissue (xylem and phloem).

Question 12.
Name the regions in which parenchyma tissue is present.
Answer:
Parenchyma is found in cortex and pith of both root and stem. When it contains chlorophyll, it is called chlorenchyma, found in green leaves.

Question 13.
What is the role of epidermis in plants?
Answer:
Cells of epidermis form a continuous layer without intercellular spaces. It protects all the parts of the plant.

Question 14.
How does the cork act as a protective tissue?
Answer:
In older plants, the secondary meristem forms on its outerside several layered thick cork or the bark. Cork acts as a protective tissue because:

1. Its cells are dead and compactly arranged without intercellular spaces
2. Its cells also have deposition of suberin in their walls that makes them impervious to gases and water.

Thus, cork protects the underlying tissues from excessive loss of water, adverse external environment and mechanical injuries.

Question 15.
Complete the table:

Answer:

Tissues Additional Questions

Tissues Multiple Choice Questions

Question 1.
The spindle shaped cells, uninucleated and unbranched are present in muscular tissue of _________.
(a) Striated muscles
(b) Smooth muscles
(c) Cardiac muscles
(d) Both (a) and (b).
Answer:
(b) Smooth muscles

Question 2.
The size of the stem increases in the width due to _________.
(a) Apical meristem
(b) Intercalary meristem
(c) Primary meristem
(d) Lateral meristem.
Answer:
(d) Lateral meristem.

Question 3.
The cells of cork are dead and have a chemical in their walls that makes them impervious to gas and water. The chemical is _________.
(a) Lignin
(b) Suberin
(c) Cutin
(d) Wax.
Answer:
(b) Suberin

Question 4.
The tissue that helps in the movement of our body are _________.
(a) Muscular tissue
(b) Skeletal tissue
(c) Nervous tissue
(d) All of the above.
Answer:
(d) All of the above.

Question 5.
The connective tissue that connects muscle to bone is called _________.
(a) Ligament
(b) Tendon
(c) Cartilage
(d) Areolar.
Answer:
(b) Tendon

Question 6.
Cartilage and bone are types of _________.
(a) Muscular tissue
(b) Connective tissue
(c) Meristematic tissue
(d) Epithelial tissue.
Answer:
(b) Connective tissue

Question 7.
A tissue whose cells are capable of dividing and re – dividingis called _________.
(a) Complex tissue
(b) Connective tissue
(c) Permanent tissue
(d) Meristematic tissue.
Answer:
(d) Meristematic tissue.

Question 8.
The tissue that helps in the secretion and absorption and is found in the inner lining of the alimentary canal is?
(a) Ciliated epithelium
(b) Cuboidal epithelium
(c) Squamous epithelium
(d) Columnar epithelium.
Answer:
(d) Columnar epithelium.

Question 9.
The flexibility in plants is due to a tissue called?
(a) Chlorenchyma
(b) Parenchyma
(c) Sclerenchyma
(d) Collenchyma.
Answer:
(d) Collenchyma.

Question 10.
The tissue present in the lining of kidney tubules and ducts of salivary glands is?
(a) Squamous epithelium tissue
(b) Glandular epithelium tissue
(c) Cuboidal epithelium tissue
(d) Columnar epithelium tissue.
Answer:
(d) Columnar epithelium tissue.

Tissues Very Short Answer Type Questions

Question 1.
Name two main groups of plant tissue.
Answer:
Two groups are:

1. meristematic tissues and
2. permanent tissues.

Question 2.
Where will you look for meristematic cells in a plant body?
Answer:
The meristematic cells are present only at the growing regions such as shoot tips, root tips and at the base of the leaves or internodes.

Question 3.
What are simple permanent tissues?
Answer:
Simple permanent tissues consist of one type of cells which look like each other.

Question 4.
Name two types of simple permanent plant tissues.
Answer:
Simple permanent plant tissues are:

1. Parenchyma
2. Collenchyma and
3. Sclerenchyma.

Question 5.
Write four elements of xylem.
Answer:

1. Tracheids
2. Vessels
3. Xylem parenchyma
4. Xylem fibres.

Question 6.
What are the three types of muscle fibres (muscle cells)?
Answer:
Three types of muscle fibres are:

1. Striated muscle (skeletal muscle or voluntary muscle).
2. Unstriated muscle (smooth muscle or involuntary muscle).
3. Cardiac muscle.

Question 7.
What are the various functions of all types of epithelial tissues?
Answer:
Epithelial tissues help in

1. protection
2. absorption
3. excretion
4. exchange of respiratory gases
5. secretion.

Question 8.
What is basement membrane?
Answer:
It is a very thin non – cellular membrane on which cells of epithelial tissue rest. It also separates the epithelial tissue from the underlying tissues.

Question 9.
Of which type of muscles the stomach wall is made of? Whether they are voluntary or involuntary?
Answer:
Smooth or non-striated. They are involuntary muscles.

Question 10.
What is the function of connective tissue?
Answer:
Connective tissue connects different tissues and organs. It provides support to different parts of the body by forming packing around different organs of the body

Question 11.
What are the two main features of connective tissue?
Answer:

1. Cells are loosely spaced and are embedded in matrix.
2. Matrix may be jelly – like, fluid, dense or rigid.

Question 12.
Name one animal whose whole skeleton is made of cartilage.
Answer:
Shark fish.

Question 13.
List seven examples of connective tissue.
Answer:

1. Bone
2. Cartilage
3. Tendons
4. Ligaments
5. Areolar tissue
6. Adipose tissue and
7. Blood.

Question 14.
What are blood platelets?
Answer:
Blood platelets are minute (about 2 to 4μ in diameter), anucleated, disc like bodies. The main function of platelets is to help in clotting of blood.

Question 15.
Name the connective tissue that is found between skin and muscles.
Answer:
Areolar connective tissue fills the space between skin and muscles.

Question 16.
How would you recognize that the slide given to you is of striated muscle? Give only two important points.
Answer:

1. Striated muscles have light and dark bands (which gives it a striped look).
2. Striated muscle fibres are not branched like cardiac muscles.

Question 17.
From which part of a nerve cell, dendrites arise?
Answer:
The cell body.

Question 18.
Name the tissue present in the brain.
Answer:
Nervous tissue (formed of neuron cells).

Question 19.
Which cell is the longest in the body of an animal?
Answer:
Neuron (Nerve cell) which may be upto 1m long (in special cases).

Question 20.
Name a fluid, except blood, which circulates in the body.
Answer:
Lymph.

Question 21.
Why are striated muscles generally called skeletal muscles?
Answer:
In general, striated muscles are attached with the bones. They help in the movement of the bones. So, they are also called skeletal muscles.

Question 22.
Name one muscle which does not fatigue and works throughout life in normal conditions.
Answer:
Cardiac muscles.

Question 23.
How are ligaments different from tendons?
Answer:
Ligaments are elastic connective tissues which attach bones with each other to keep them in then placer Tendons arc less elastic connective tissues which attach, muscles to a bone.

Question 24.
What is the main function of meristematic tissue?
Answer:
The mam function of meristematic tissue is to form continuously new cells for increasing cell number, length and the girth of the plant.

Tissues Short Answer Type Questions

Question 1.
How do tissues formed in multicellular organisms?
Answer:
During development from zygote (formed by the union of egg and sperm), a large number of cells are formed. These cells undergo differentiation to produce various specialised tissues to perform different functions in the living body.

Question 2.
What are the characteristics of plant tissues?
Answer:
Plants are stationary or fixed, they do not need much energy. So, most of the tissues they have are supportive, which provide them with structural strength. Most of these tissues are dead; they do not contain living protoplasm.

Question 3.
What are structural and functional differences between plants and animals?
Answer:
As plants do not move, they do not need much energy. So, most of the tissues they have are dead and supportive. But animals need energy as they move around in search of food, mate and shelter. So, most of the animal tissues are living.

Question 4.
Why do meristematic cells lack vacuoles?
Answer:
Meristematic cells divide frequently to give rise to new cells. So, they need dense cytoplasm and soft cell wall. Vacuoles cause hindrance in cell division as they are full of cell sap and provide turgidity and rigidity to the cell.

Question 5.
What are characteristic structural features of meristematic cells ?
Answer:
Meristematic cells have:

1. Thin cell walls.
2. Abundant or dense cytoplasm and single large nucleus.
3. Spherical, oval, polygonal or rectangular shape.
4. No intercellular spaces between them.
5. Either no vacuoles at all or a few vacuoles.

Question 6.
List any four salient features of meristematic tissue.
Answer:

1. This tissue consists of actively dividing cells.
2. This tissue is present in growing regions of plants.
3. In this tissue, cells are packed closely without intercellular spaces.
4. Cells of this tissue have thin cell walls, dense cytoplasm and prominent nuclei.

Question 7.
What are permanent tissues?
Answer:
The cells of meristematic tissue lose the ability to divide and get differentiated into specialised cells. These differentiated cells form different types of tissues which are known as permanent tissues.
Some examples: permanent tissues are

• parenchyma
• sclerenchyma etc.

Question 8.
With the help of only schematic line diagram, show classification of main permanent tissues.
Answer:

Question 9.
Write the characteristics of collenchyma.
Answer:
The cells in this type of tissue are living, elongated and thickened with cellulose at the corners. There is very little intercellular space. This tissue provides flexibility and mechanical support to plants. It is found in hypodermis of stems and leaf stalks.

Question 10.
What are protective tissues?
Answer:
All parts of plants e.g., leaves, flowers, stems and roots are covered by a single outermost protective layer called epidermis. It consists of rectangular, closely fitted relatively flat cells which lack intercellular spaces. Usually, it is one cell thick and is covered with cutin. Epidermis protects internal tissues of the plant.

Question 11.
Does the outer most protective layer is throughout, continuous? If not, what interruptions are usually foundation leaves and herbaceous parts of the plant?
Answer:
Epidermis is the outermost layer of cells in leaves and green herbaceous stems. It is not a continuous layer as it contain numerous minute pores called stomata.

Question 12.
Write major functions of stomata present in the epidermis.
Answer:
Major functions of stomata:

1. Stomata are essential for exchange of gases – oxygen and carbon dioxide between the plant and the atmosphere.
2. Normally, plants remove excessive water in the form of vapour through stomata. This process is called transpiration.

Question 13.
What is the main function of vascular tissues in plants?
Answer:
Vascular tissues transport:

1. Water and dissolved minerals from toots to various parts of the plant (xylem).
2. Prepared food material from leaves to different plant parts (phloem).

Question 14.
What ire vascular bundles?
Answer:
In plants, complex tissues xylem and phloem altogether constitute a structure called vascular bundle. Their main function is transportation of water, salts and food materials within the plant body.

Question 15.
List four elements of phloem. Which one of them is most important and why?
Answer:
Phloem consists of following four elements:

1. Sieve tubes
2. Companion cells
3. Phloem parenchyma
4. Phloem fibres.

The most important element of phloem is sieve tubes because they translocate food materials from leaves to other parts of plant.

Question 16.
What is muscular tissue? What is their function?
Answer:
1. Muscular tissue: This is a specialised tissue which is composed of contractile, fibre – like cells. This tissue is responsible for movement in our body.

2. Function: The movement of the body or limbs is brought about by contraction and relaxation of contractile proteins present in the muscle cells.

Question 17.
In desert plants, epidermis is covered by waxy substances. Can you think why?
Answer:
Waxy substances which cover epidermis are waterproof and hence, they check loss of water during transpiration. Besides this, they also aid in protection against mechanical injury and invasion by parasitic fungi.

Question 18.
What are the four important types of tissues found in animals?
Answer:
The four animal tissues found in animals are:

1. Epithelial tissues.
2. Connective tissues.
3. Muscular tissues and.
4. Nervous tissue.

Question 19.
State one important function of each of the following:

1. Areolar tissue
2. Cuboidal epithelium.

Answer:

1. Areolar tissue: It fills the space inside the organs, supports internal organs and helps in repair of tissues.
2. Cuboidai epithelium: it forms the lining of kidney tubules and ducts of salivary glands where it provides mechanical support.

Question 20.
What are the two main components of blood? Why is blood considered a type of connective tissue?
Answer:
Blood has two main components:

1. Fluid (liquid) matrix called plasma.
2. Suspended red blood cells (RBCs), white blood cells (WBCs) and platelets.

Blood is considered as a connective tissue because:

1. It has the same Origin as the other connective tissues.
2. It flows to different parts of the body and thus, connects different parts of the body with one another to exchange materials and gases.

Question 21.
Why do blood and lymph called as connective tissues?
Answer:
The fluid tissue (blood and lymph) connects various parts (cells) of the body. It supplies nutritive materials, oxygen and hormones collected from different organs to the body tissues. It also collects waste materials from different body tissues and delivers to excretory organs.

Question 22.
Why is blood called as fluid connective tissue?
Answer:
Blood is considered as a connective tissue because it connects different parts of the body. It contains plasma as matrix in which blood cells remain suspended. Being matrix (plasma) in liquid state, blood is called fluid connective tissue.

Question 23.
Explain how the bark of a tree is formed. How does it act as a protective tissue?
Answer:
As trees grow old, a strip of secondary meristem replaces the epidermis of the stem. Cells on the outside are cut off from this layer. This forms the several layer thick cork or the bark of the tree. Bark is a mass of dead tissue lying in the peripheral region of the plant body as a hard dry covering. Its function is protection. It protects the inner tissues against the attack of fungi and insects, against loss of water by evaporation etc.

Question 24.
What is the difference between voluntary and involuntary muscles? Give example of each.
Answer:
Voluntary muscles are those which are directly under control of our will
e.g.

• skeletal muscle.

They work or contract on our command. Involuntary muscles are not under the command of our will. We cannot control contraction and relaxation of these muscles. They are of two types – smooth muscles and cardiac muscles. Smooth muscles are found in stomach, intestine, iris of eye, in ureters and in the bronchi of lungs. Another type of involuntary muscles that is, cardiac muscles are found in heart.

Tissues Long Answer type Questions

Question 1.
The following diagrams are of L.S. of shoot apex and L.S. of root apex. Observe the diagrams and answer the questions given below:

1. What type of cells shoot apex and root apex consists of?
2. What are the main characteristics of these cells?
   

Answer:

1. Meristematic cells.
   • (a) Cells have big nucleus and dense cytoplasm.
   • (b) These cells lack intercellular spaces and vacuoles.

Question 2.
How many types of meristems are present in plants, on the basis of position?
Answer:
On the basis of location of meristem, it is classified into three types:

1. Apical meristem: It is present at the tip of stem, root and their branches.

2. Intercalary meristem: It is found at the leaf base, above the nodes (i.e. at the base of internodes as in grasses) or below the nodes (i.e. at the upper most region of internode as in mint.)

3. Lateral meristem: Vascular cambium and cork cambium are the examples of lateral meristem. Vascular cambium is found in vascular bundles while cork cambium is found underneath the bark of trees. Both of these cause increase in the girth of plants.

Question 3.
Draw a labelled diagratn of shoot to show location of meristematic tissues in the plant body and write the functions of each of them.
Answer:
Functions:

1. Apical meristem: It increases the length of the stem and the root.
2. Lateral meristem (cambium): It increases the girth of the stems and roots.
3. Intercalary meristem: It is present at the base of the leaves or internode (on either side of the node).

It produces buds which develop in auxiliary branches or auxiliary floral branches.

Question 4.
Explain the structure of parenchyma. What are its major modifications?
Answer:
Parenchyma: It is the basic or fundamental tissue found in plants. Cells of this tissue are thin walled, circular or polygonal. They are living with a nucleus and a vacuole. Intercellular spaces are present between the cells of this tissue. Two modifications of parenchyma are chlorenchyma and aerenchyma.

Chlorenchyma: Sometimes cells of the parenchyma contain chlorophyll and perform photosynthesis. This kind of parenchyma is known as chlorenchyma.

Aerenchyma: In aquatic plants, parenchyma contains big air spaces in between them. Such a parenchyma tissue is known

(a) Parenchyma with intercellular spaces.
(b) Aerenchyma with big spaces

Question 5.
Write the main functions of parenchyma.
Answer:
Functions of the parenchyma:

1. They store food.
2. They provide temporary support by retaining the turgid condition of cells.
3. Chlorenchyma containing chloroplasts prepare food through photosynthesis.
4. In aquatic plants, aerenchyma gives buoyancy to plants and hence they can float easily.

Question 6.
Describe the structure of selerenchyma. Write its major functions.
Answer:
Selerenchyma: Selerenchyma is the chief mechanical tissue of plants. The cells of this tissue are usually long, narrow and pointed at both ends. Due to deposition of lignin, their walls are often very highly thickened. Hence, the lumen of cell cavity is nearly obliterated. They are usually provided with simple pits which may be oblique or straight.
The selerenchyma cells are dead cells and their main function is to provide strength and rigidity to the plant.

Question 7.
What is xylem? Explain its structure. Which one of its component is very important and why?
Answer:
Xylem is a complex plant tissue which transports water and dissolved minerals from roots to all other plant parts.

Structure: Xylem consists of four kinds of cells (also known as elements):
(i) Tracheids: A tracheid is an elongated, hollow cell with its both ends tapering. The walls of these cells are thickened by the deposition of lignin. At certain spots lignin is not present. These spots are termed as pits. The tracheids are dead cells.

(ii) Vessels: These are tube like structures formed by a number of cells placed end to end with their transverse walls dissolved. The side walls of these tubes also have deposition of lignin. The thickening of the walls show various kinds of patterns. They are also dead cells.

(iii) Xylem parenchyma: These are parenchymatous, thin walled, living cells. They help in lateral conduction of water and sap. They also store food.

(iv) Xylem fibres: They are lignified dead fibres which provide mechanical support to plant. The most important element of xylem is vessel because most of the water and minerals are carried upward through this component of xylem.

Question 8.
Describe the structure of phloem.
Answer:
Structure of phloem: The main conducting part of the phloem is sieve tube which is formed of elongated cylindrical cells arranged in vertical rows. The walls between the cells have many minute pores through which food material can pass from one cell to the next. The porous walls between the cells is termed as sieve plate. Each sieve tube is supported by a long parenchymatous cell called the companion cell which helps the sieve tubes in the conduction of food material.

The above figure shows that phloem also contains phloem fibres, which provide mechanical support. Another component of phloem is parenchyma cells which stores food.

Question 9.
What is epithelial tissue?
Answer:
Epithelial Tissue: Epithelial tissue forms covering of entire surface of the body and lines the internal organs. Because of this, epithelial tissue is also called protective tissue. It also forms a barrier to keep different body systems separate. In this tissue cells are closely associated and arranged on a very thin extracellular fibrous basement membrane. Epithelial tissue may be composed of one (simple epithelium) or more layers of cells (compound epithelium). The skin, lining of mouth and alimentary canal, lung alveoli etc. are made of epithelial tissues.

Question 10.
What are the four main functions of epithelial tissue?
Answer:
The four main functions of epithelial tissue are:

1. It forms the outer layer of skin and hence it protects the underlying cells from drying, injury, bacterial and chemical effects..
2. It forms lining of mouth, alimentary canal and other internal organs and thus protects these organs.
3. It helps in absorption of water and other nutrients in alimentary canal.
4. Some of them are greatly specialised and perform secretory function.

Question 11.
What are the categories of epithelial tissue depending upon the shape and function of epithelial cells?
Answer:
Depending upon the shape and function of the cells, epithelial tissue is classified as:

Question 12.
What are the various forms of epithelial tissues? Describe briefly.
Answer:
(i) Squamous epithelium: The cells of this tissue are thin and flat forming a delicate lining. It is found in the alveoli and blood vessels. Tongue, oesophagus and lining of mouth also made up of squamous epithelium.

(ii) Cuboidal epithelium: The cells of this tissue are cube like in appearance. It is found in the lining of kidney tubules and ducts of salivary glands etc.

(iii) Columnar epithelium: The cells of this tissue are more tall and wide, placed side by side. Their nuclei are situated near the bases. They may have finger like . projections – the microvilli on their free surfaces. This tissue usually lives in the internal surface of stomach and intestine.

(iv) Ciliated epithelium: The cells of this tissue are modifications of columnar epithelial cells. They have many small hair like projections called cilia on their free ends. This type of epithelium is found in trachea and oviduct.

(v) Striated squamous epithelium: Cells of this tissue are similar to squamous epithelial cells but in this tissue they are arranged in many layers to prevent wear and tear of parts. In skin, striated squamous epithelium is found.

(vi) Glandular epithelium: In this type of epithelium, cells secrete substances at the epithelial surface. Such type of epithelium is found in glands.

Question 13.
Explain the structure of three types of muscle fibres. Also write the locations where they are found in the body.
Answer:
The following are the three types of muscle cells:
(i) Unstriated muscles: (Also known as smooth, involuntary muscles). This type of muscular tissue consists of spindle – shaped, long uninucleate cells. These muscles are present in alimentary canal, blood vessels, iris of eye, in ureters and bronchi of lungs etc.

(ii) Striated muscles: Also known as voluntary muscles because of their function being in our control or will. This type of muscular cells are long multi – nucleated and, enclosed in a membrane known as sarcolemma. Each fibre has several longitudinal filaments embedded in cytoplasm. These filaments give these muscles striated appearance. These muscles are attached to the skeleton; so they are also called skeletal muscles.

(iii) Cardiac muscles: These muscles are found in heart. They are not under the control of the will. They contract rhythmically and involuntarily throughout life without the sign of fatigue. Structurally they show the characters of both unstriated and striated muscles. They are made up of branched fibres. These fibres are uninucleated and show alternate light and dark bands (striations).

Question 14.
What are three main categories of connective tissue?
Answer:
Categories of Connective Tissue:
(i) Connective tissue: There is a matrix in which generally two types of (white and yellow) fibres are present. In between these fibres some connective tissue cells are present.
Examples of this kind of connective tissues are

• areolar tissue and
• adipose tissue.

(ii) Skeletal tissue: This type of tissue forms the skeleton of an organism. It is of two types – cartilage and bone Cartilage has solid matrix, called chondrin, in which fibres and cells known as chondrocytes are present. Usually, cells are present in clusters of 2 – 3 cells in small spaces called lacunae. Cartilage is found in the regions of pinna, nose, trachea and larynx. In bones, matrix is formed of a protein called ossein impregnated with phosphate and carbonates of calcium and magnesium.

(iii) Fluid tissue: Blood and lymph are examples of fluid connective tissue. These are specialized connective tissues. It consists of liquid matrix with no fibres. In liquid matrix called plasma corpuscles remain suspended. Blood transports food material, gases and other substances to the various parts of the body.

Question 15.
What are fibrous connective tissue?
Answer:
Fibrous connective tissue. It is of two types:
(i) The white fibrous connective tissue: It consists of white, non-elastic, unbranched fibres which unite to form bundles called tendons. Tendons are strong, tough and smooth, rope like structures which serve to attach muscles with the bones.

(ii) The yellow fibrous connective tissue: It also consists of fibres which are fine thread like structures. These fibres are quite elastic. Like white elastic fibres, these fibres also form cords called ligaments. These ligaments connect two bones.

Question 16.
Describe the structure of cartilage and bone.
Answer:
1. Cartilage: It is a solid but semi – rigid and flexible connective tissue. It has large, bluntly angular cartilage cells called chondrocytes. They occur in clusters of 2 or 3 in small spaces (lacunae) scattered in the matrix. Cartilage smoothens bone surfaces at joints and is also present in the nose, ear, trachea and larynx.

2. Bone: Bone is a solid, rigid and strong connective tissue. Its matrix become hard due to the deposition of salts of calcium and phosphorus. Osteocytes or bone cells are present in irregular spaces – lacunae in the matrix, interconnected by fine canals called canaliculi. In this tissue, matrix deposits in concentric rings around narrow longitudinal cavities called Haversian canals. These canal carries blood vessels and nerves.

Question 17.
Explain the structure of a fluid connective tissue.
Answer:
Blood is a fluid connective tissue consists of:

1. Blood plasma: It is the fluid matrix which contains 85% to 90% water, 7% different types of proteins, 0.9% of salts, about 0.1% glucose and a very small amount of hormones, wastes etc. In the plasma, blood corpuscles (cells) are suspended.
2. Blood cells. Three kinds of blood cells are found suspended in the blood plasma.

These are:
(a) Red blood corpuscles (erythrocytes) or RBC
(b) White blood corpuscles (leucocytes) or WBC and
(c) Blood platelets.

(a) Red blood corpuscles (erythrocytes) or RBC:
The red blood corpuscles are biconcave, disc – like cells which are devoid of nucleus. They contain a substance called haemoglobin because of this they appear red in colour. The most important function of the RBC is the transport of oxygen and carbon dioxide.

(b) White blood corpuscles (leucocytes) or WBC: These cells are comparatively larger in size, colourless and irregular in appearance. They are devoid of haemoglobin. They protect our body from diseases by destroying germs.

(c) Blood platelets: These are small, 2 – 4μ in diameter. They are without nucleus. Their main function is to liberate some substances which helps in blood clotting.

Question 18.
What are areolar tissue and adipose tissue? Where are they located?
Answer:

1. Areolar tissue: It is a connective tissue which consists of matrix, several types of cells, collagen and elastin fibres.
2. Location: They are found between the skin and muscles, around blood vessels and nerves and in the bone marrow.
3. Functions: It fills space inside the organs, support internal organs and helps in repair of the tissues.
   
4. Adipose tissue: It consists of cells (adipocytes) which are filled with fat globules. These cells remain scattered in a matrix.
5. Location: It is found below the skin and between internal organs.
6. Function: It stores fats and act as insulator.
   

Question 19.
(i) What is a nervous tissue?
(ii) Draw a well labelled diagram of neuron. (label any 4 parts).
Answer:
(i) Nervous Tissue: Nervous tissue is made up of specialised cells called nerve cells or neurons. Each nerve cell is elongated in shape and consists of three parts: cell body, dendrites and axon.The cell body contains a distinct nucleus and has a special kind of granules, called Nissel’s granules in the cytoplasm. From the cell body a single long part called the axon and many branched parts called dendrites arise. In some nerve cells, the axon has a thick white covering called medullary sheath. The terminal end of axon is without sheath and branched. Each nerve cell receives message through the dendrites and sends them to the axon (see Fig. below).
(ii)

Tissues Higher Order Thinking Skills (HOTS)

Question 1.
Cutting of rose plant is done timely in gardens, but still it regain its length. Give reason.
Answer:
In rose plant, intercalary meristeim is present at the base of leaves or internodes. The cells of these tissues, therefore divide and increase the length of plant.

Question 2.
Why does water hyacinth floats on water?
Answer:
A type of parenchyma called aerenchyma is present in water hyacinth. This encloses a lot of air and makes the plant lighter than water. Therefore, it floats on water.

Tissues Value Based Question

Question 1.
A patient suffering from paralysis was unable to walk. His family members took the utmost care of him:

1. Name two tissues responsible for the movement of body?
2. What are the tissues present in brain and spine?
3. What value of the family members is seen in the above case?

Answer:

1. Two tissues responsible for movement of the body are nervous tissue and muscular tissue.
2. The tissues present in brain and spine are nervous tissues.
3. His family members showed the value of being kind, caring, dutiful and responsible.

MP Board Class 9th Science Solutions

MP Board Class 9th Maths Solutions Chapter 7 Triangles Ex 7.3

Question 1.
∆ABC and ∆DBC are two isosceles triangles on the same base BC and vertices A and D are on the same side of BC (see Fig. below). If AD is extended to intersect BC at P, show that

1. ∆ABD = ∆ACD
2. ∆ABP = ∆ACP
3. AP bisects ∠A as well as ∠D.
4. AP is the perpendicular bisector of BC.

Solution:
Given
AB = AC
DB = DC
To prove:

1. ∆ABD = ∆ACD
2. ∆ABP = ∆ACP
3. ∠1 = ∠2 and ∠5 = ∠6
4. ∠3 = ∠4 = 90° and BP = PC

Proof
1. In ∆ABD and ∆ACD
AB = AC (given)
BD = CD (given)
AD =AD (common)
∆ABD = ∆ACD (by SSS)
and so ∠1 = ∠2 (by CPCT)

2. In ∆ABP and ∆ACP
AB = AC (given)
∠1 = ∠2 (proved)
AP = AP (common)
∆ABP ≅ ∆ACP (by SAS)
and so ∠3 = ∠4
and BP = CP (by CPCT)

∠1 = ∠2 AP bisects ∠A

3. In ∆DBP and ∆DCP
BP = CP (proved)
∠3 = ∠4 (proved)
DP = DP (common)

∆DBP ≅ ∆DCP (by SAS)
and so ∠5 = ∠6 (by CPCT)
∴ AP bisects ∠D.

4. BP = CP (proved)
∠3 = ∠4 (proved)
∠3 + ∠4 = 180° (LPA’s)
∠3 + ∠3 = 180° (∠3 = ∠4)
2∠3 = 180°
∠3 = 90°
∠3 = ∠4 (each 90°)
and therefore, AP is the perpendicular bisector of BC

Question 2.
AD is an altitude of an isosceles triangle ABC in which AB = AC. Show that

1. AD bisects BC
2. AD bisects ∠A.

Solution:
Given
AB = AC and AD ⊥ BC
To prove
∠1 = ∠2 and
BD = CD
Proof:
In ∆ABD and ∆ACD
AB = AC
AD = AD
∠3 = ∠4
∆ABD = ∆ADC
and so BD = CD and ∠1 = ∠2

Question 3.
Two sides AS and BC and median AM on one triangle ABC are respectively equal to sides PQ and QR and median PN of ∆PQR (see-Fig. below). Show that:

1. ∆ABM ≅ ∆PQN
2. ∆ABC ≅ ∆PQR

Solution:
Given
AB = PQ
BC = QR
AM = PN
To prove:

1. ∆ABM ≅ ∆PQN
2. ∆ABC ≅ ∆PQR

Proof:
BC = QR (given)
\(\frac{1}{2}\) BC = \(\frac{1}{2}\)QR
BM = QN

1. In ∆ABM and ∆PQN
AB = PQ (given)
BM = QN (proved)
AM = PN (given)
∆ABM ≅ ∆PQN (by SSS)
and so ∠ABC = ∠PQR (by CPCT)

2. In ∆ABC and ∆PQR
AB = PQ (given)
BC = QR (given)
∠B = ∠Q (proved)
∆ABC ≅ ∆PQR by (SAS)

Question 4.
BE and CF are two equal altitudes of a triangle ABC. Using RHS congruence rule, prove that triangle ABC is isosceles.

Solution:
Given
∠E = ∠F
BE = CF
To prove
AB = AC
Proof:
In ∆FBC and ∆ECB
BE = CF (given)
∠F = ∠E (each 90°)
BC = CB (common)
∴ ∆FBC = ∆ECB (by RHS)
and so ∠B = ∠C (by CPCT)
In ∆ABC, ∠B = ∠C
AB = AC
(sides opposite to equal angles of a A are equal)
and so ABC is isosceles.

Question 5.
ABC is an isosceles triangle with AB = AC. Draw AP ⊥ BC to show that ∠B = ∠C.
Solution:
Given
AB = AC
∠APB = ∠APC = 90°
To prove:
∠B = ∠C

Proof:
In ∆ABP and ∆ACP
AP = AP (common)
∠APB = ∠APC (each 90°)
AB = AC (given)
∴ ∆ABP = ∆ACP (by RHS)
and ∠B = ∠C (by CPCT)

Theorem 7.6.
If two angles of a triangle are equal, then the sides opposite to them are also equal.
Given
In ∆ABC, ∠C = ∠B

To prove: AB = AC
Construction:
Draw the bisector of ∠A and let it meet BC an D
Proof:
In ∆s ABD and ACD, we have ∠B = ∠C (Given)
∠BAD = ∠CAD (Construction)
AD = AD (Common)
∴ ∆ABD ≅ ∆ACD (AAS Cong. Criterion)
Hence, AB = AC (CPCT)

Theorem 7.7.
If two sides of a triangle are unequal, the longest side has greater angle opposite to it.
Given:
In ∆ABC; AC > AB
To prove: ∠ABC > ∠ACB.

Construction:
Mark point D on AC such that AB = AD. Join BD.
Proof:
In ∆ABD,
AB = AD
∴ ∠1 = ∠2 (Const. As opp. equal sides) ….(1)
But ∠2 is an exterior angle of ABCD.
∠2 > ∠ACB (Exterior Angle Theorem) …(2)
From (1) and (2), we have
∠1 > ∠ACB (Const.)
But ∠ABC > ∠1
∴ ∠ABC > ∠ACB

Theorem 7.8. (Converse of Theorem 7.7)
In a triangle the greater angle has the longer side opposite to it.
Given:
In ∆ABC, ∠ABC > ∠ACB
To prove: AC > AB

Proof:
For ∆ABC, there are only three possibilities of which exactly one must be true.

1. AC = AB
2. AC < AB (iii) AC > AB.

Case 1:
If AC = AB, then ∠ABC = ∠ACB, which is contrary to what is given.
AB ≠ AC

Case 2:
If AC < AB, the longer side has the greater angle opposite to it.
∴ ∠ACB > ∠ABC.
This is also contrary to what is given.

Case 3:
We are left with the only possibility, namely AC > AB which is true.
AC > AB.

MP Board Class 9th Maths Solutions

MP Board Class 9th Science Solutions Chapter 9 Force and Laws of Motion

Force and Laws of Motion Intext Questions

Force and Laws of Motion Intext Questions Page No. 118

Question 1.
Which of the following has more inertia:

1. a rubber ball and a stone of the same size?
2. a bicycle and a train?
3. a five – rupees coin and a one – rupee coin?

Answer:
As we know, inertia is the calculated value for the mass of the body. It is proportional to mass of the body:

1. Inertia of the stone is greater than that of a rubber ball as mass of a stone is more than the mass of a rubber ball for the same size.
2. Inertia of the train is greater than that of the bicycle. As mass of a train is more than the mass of a bicycle.
3. Mass of a five rupee coin is more than that of a one – rupee coin. Hence, inertia of the five – rupee coin is greater than that of the one – rupee coin.

Question 2.
In the following example, try to identify the number of times the velocity of the ball changes: “A football player kicks a football to another player of his team who kicks the football towards the goal. The goalkeeper of the opposite team collects the football and kick it towards a player of his own team”. Also, identify the agent supplying the force in each case.
Answer:
Four times:

• First, when a football player kicks to another player. Agent supplying the force: First case – First player. Second when that player kicks the football to the goalkeeper. Agent supplying the force. Second case – Second player.
• Third when the goalkeeper stops the football. Agent supplying the force: Third case – Goalkeeper.
• Fourth when the goalkeeper kicks the football towards a player of his own team. Agent supplying the force: Fourth case – Goalkeeper.

Question 3.
Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.
Answer:
When we shake any tree’s branches vigorously some leaves of that tree get detached because branches comes in motion while the leaves tend to remain at rest due to inertia of rest.

Question 4.
Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?
Answer:
Due to inertia of motion, we fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest.

1. Case I: Since the driver applies brakes and bus comes to rest. But, the passenger tries to maintain its inertia of motion. As a result, a forward force is exerted on him.
2. Case II: The passenger tends to fall backwards when the bus accelerates from rest because when the bus accelerates, the inertia of rest of the passenger tends to oppose the forward motion of the bus.

Force and Laws of Motion Intext Questions Page No. 126

Question 1.
If action is always equal to the reaction, explain how a horse can pull a cart.
Answer:
According to Newton’s third law of motion, a force is exerted by the Earth on the horse in the forward direction while horse pushes the ground in the backward direction. As a result, the cart moves forward.

Question 2.
Explain, why is it difficult for a fireman to hold a hose, which ejects large amounts of water at a high velocity.
Answer:
According to Newton’s third law of motion, a reaction force is exerted over fireman by the ejecting water in the backward direction when a fireman holds a hose, which is ejecting large amounts of water at a high velocity. As a result of the backward force, the stability of the fireman get affected. Hence, it is difficult for him to remain stable while holding the hose.

Question 3.
From a rifle of mass 4kg, a bullet of mass 50g is fired with an initial velocity of 35 ms^-1. Calculate the initial recoil velocity of the rifle.
Answer:
Given,
Mass of the rifle, m₁ = 4kg
Mass of the bullet, m₂ = 50g = 0.05kg
Recoil velocity of the rifle = v₁
Bullet is fired with an initial velocity, v₂= 35 m/s
Condition:
Initially, the rifle is at rest.
Thus, its initial velocity, v = 0
Total initial momentum of the rifle and bullet system = (m₁+ m₂)v = 0
Total momentum of the rifle and bullet system after firing = m₁v₁ + m₂v₂
= 0.05 × 35 = 4v₁ + 1.75
As per law of conservation of momentum:
Total momentum after the firing = Total momentum before the firing
⇒ 4v₁ + 1.75 = 0
v₁ = –\(\frac { 1.75 }{ 4 }\) = -0.4375 m/s
So, the rifle recoils backwards with a velocity of 0.4375 m/s because value is negative.

Question 4.
Two objects of masses 100g and 200g are moving along the same line and direction with velocities of 2 ms^-1 and 1  ms^-1, respectively. They collide and after the collision, the first object moves at a velocity of 1.67 ms^-1. Determine the velocity of the second object.
Answer:
Given,
m₁ = 100g = 0.1kg
m₂ = 200g = 0.2kg
Velocity of m₁ before collision, v₁ = 2 m/s
Velocity of m₂ before collision, v₂ = 1 m/s
Velocity of m₁ after collision, v₃ = 1.67 m/s
Velocity of m₂ after collision = v₄
As per the law of conservation of momentum:
Total momentum before collision = Total momentum after collision
Hence,
m₁v₁ + m₂v₂ = m₁v₃+ m₂v₄
Putting values
2(0.1) + 1(0.2) = 1.67(0.1) + v₄(0.2)
0.4 = 0.167 + 0.2v₄
v₄ = 1.165 m/s
Velocity of the second object = 1.165 m/s.

Force and Laws of Motion NCERT Textbook Exercises

Question 1.
An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non –  zero velocity? If yes, state the conditions that must be placed on the magnitude and direction of the velocity. If no, provide a reason.
Answer:
Yes, an object may travel with a non – zero velocity even when the net external force on it is zero. A rain drop falls down with a constant velocity. The weight of the drop is balanced by the upthrust and the viscosity of air. The net force on the drop is zero.

Question 2.
When a carpet is beaten with a stick, dust comes out of it Explain.
Answer:
When we beat the carpet with a stick, it comes into motion. But the dust particles continue to be at rest due to inertia and get detached from the carpet.

Question 3.
Why is it advised to tie any luggage kept on the roof of a bus with a rope?
Answer:
Due to sudden jerks or due to the bus taking sharp turn on the road, the luggage may fall down from the roof because of its tendency to continue moving in the original direction. To avoid this, the luggage is tied with a rope on the roof.

Question 4.
A batsman hits a cricket ball which then rolls on a level ground. After covering a short distance, the ball comes to rest The ball slows to a stop because
(a) the batsman did not hit the ball hard enough.
(b) velocity is proportional to the force exerted on the ball.
(c) there is a force on the ball opposing the motion.
(d) there is no unbalanced force on the ball, so the ball would come to rest.
Answer:
(c) there is a force on the ball opposing the motion.

Question 5.
A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 metric tonnes (Hint: 1 metric tonne = 1000 kg.)
Answer:
Here, u = 0, s = 400m, t = 20 s, a = ?, F = ?.
m = 7 tonnes
= 7 × 1000kg
= 7000kg
⇒ s = ut + \(\frac { 1 }{ 2 }\)at²
400 = (0 + 20) + \(\frac { 1 }{ 2 }\)a(20)²
a = \(\frac { 400\times 2 }{ { 20 }^{ 2 } } \)
∴ a = 2 m/s²
Force,
F = ma
= 7000 × 2 = 14,000 N.

Question 6.
A stone of 1kg is thrown with a velocity of 20 ms^-1 across the frozen surface of a lake and comes to rest after travelling a distance of 50m. What is the force of friction between the stone and the ice?
Answer:
m = 1kg, u = 20 m/s, s = 50m, v = 0, F = ? a = ?.
⇒ v² – u² = 2as
(0)² – (20)² = 2a (50)
∴ – 400 = 100a
= \(\frac { 400 }{ 100 }\) – 4 m/s²
Force of friction, F = m × a
= 1kg × -4 m/s² = -4 N

Question 7.
A 8000kg engine pulls a train of 5 wagons, each of 2000kg, along a horizontal track. If the engine exerts a force of 40,000 N and the track offers a friction force of 5000 N, then calculate:
(a) the net accelerating force;
(b) the acceleration of the train; and
(c) the force of wagon 1 on wagon 2.
Answer:
m = 8,000 + 5 × 2,000 = 18,000kg
(a) The net accelerating force,
F = Engine force – friction force
= 40,000 – 5,000 = 35,000 N.

(b) The acceleration of the train,
a = \(\frac { F }{ m }\) = \(\frac { 35,000 }{ 18,000 }\) = \(\frac { 35 }{ 18 }\) = 1.94 ms^-2

(c) The force of wagon 1 on wagon 2
= The net accelerating force – mass of wagon × acceleration
= 35,000 – 2,000 × \(\frac { 35 }{ 18 }\)
= 35,000 – 3888.8 = 31,111.2 N.

Question 8.
An automobile vehicle has a mass of 1500kg. What must be the force between the vehicle and road if the vehicle is stopped with a negative acceleration of 1.7 ms^-2?
Answer:
Here, mass = 1500kg
a = -1.7 ms²
F = m × a
= 1500 × (-1.7)
= -2550 N
The force between the vehicle and the road is 2,550 is, m a direction opposite to the direction of the vehicle.

Question 9.
What is the momentum of an object of mass m, moving with a velocity v? Choose correct option.
(a) (mv)²
(b) mv²
(c) \(\frac { 1 }{ 2 }\) × mv²
(d) mv.
Answer:
(d) mv.

Question 10.
Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?
Answer:
The cabinet will move with constant velocity only when the net force on it is zero.
Force of friction on the cabinet = 200 N, in a direction opposite to the direction of motion of the cabinet.

Question 11.
Two objects, each of mass 1.5kg, ate moving in the same straight line but in opposite directions. The velocity of each object is 2.5 ms^-1 before the collision during which they stick together. What will be the velocity of the combined object after collision?
Answer:
Here, m₁ = m₂ = 1.5kg,
u₁ = 2.5 ms^-1, u₂ = – 2.5 ms^-1
Let v be the velocity of the combined object after the collision.
By conservation of momentum,
Total momenta after collision = Total momenta before collision
= (m₁ + m₂) v = m₁u₁ + m₂u₂
= (1.5 + 1.5) v = 1.5 × 2.5 + 1.5 × (-2.5)
= 3.0 v = 0
or
⇒ v = 0 ms^-1

Question 12.
According to the third law of motion when we push on an object, the object pushes back on us with an equal and opposite force. If the object is a massive truck parked along the roadside, it will probably not move. A student justifies this by answering that the two opposite and equal forces cancel each other. Comment on this logic and explain why the truck does not move.
Answer:
Action and reaction always act on different bodies, so they cannot cancel each other. When we push a massive truck, the force of friction between its tyres and the road is very large and so, the truck does not move.

Question 13.
A hockey ball of mass 200g travelling at 10 ms^-1 is struck by a hockey stick so as to return it along its original path with a velocity at 5 ms^-1. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.
Answer:
Here, m = 200g = 0.2kg,
u = 10 ms^-1,
v = -5 ms^-1
change in momentum = m (v – u)
= 0.2 (- 5 – 10) = -3kg ms^-1.

Question 14.
A bullet of mass 10g travelling horizontally with a velocity of 150 ms^-1 strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block. Also calculate the magnitude of the force exerted by the wooden block on the bullet.
Answer:
Here m = 10g = 0.01kg,
u = 150 ms^-1,
v = 0, t = 0.03 s
a = \(\frac { v-u\quad }{ t } \) = \(\frac { 0-150\quad }{ 0.03 } \) = -5,000 ms^-1
The distance of penetration of the bullet into the block,
s = ut + \(\frac { 1 }{ 2 }\)at²
150 × 0.03 + \(\frac { 1 }{ 2 }\) × (-5,000) × (0.03)
= 4.5 – 2.25 = 2.25
The magnitude of the force exerted by the wooden block on the bullet
= ma = 0.01 × 5,000 = 50 N.

Question 15.
An object of mass 1kg travelling in a straight line with a velocity of 10 ms^-1 collides with, and sticks to, a stationary wooden block of mass 5kg. Then, they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the impact. Also, calculate the velocity of the combined object.
Answer:
Here, m₁ = 1kg, u₁ = 10 ms^-1, m₂ = 5kg, u₂ = 0
Let v be the velocity of the combined object after the collision.
Total momentum just before the impact
= m₁u₁ + m₂u₂  = 1 × 10 + 5 × 0 = 10kg ms^-1
Total momentum just after the impact = (m₁ + m₂)v = (1 + 5)v
= 6v kg ms^-1 by conservation of momentum,
6v = 10
= v = \(\frac { 10 }{ 6 }\) = \(\frac { 5 }{ 3 }\) ms^-1
∴ Total momentum just after the impact
= 6 × \(\frac { 5 }{ 3 }\) = 10 ms^-1

Question 16.
An object of mass 100kg is accelerated uniformly from a velocity of 5 ms^-1 to 8 ms^-1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.
Answer:
Here, m = 100kg,
u = 5 ms^-1,
v = 8 ms^-1,
t = 6 s
Initial momentum, P₁ = mu = 100 × 5 = 500kg ms^-1
Final momentum, P₂ = mu = 100 × 8 = 800kg ms^-1
The magnitude of the force exerted on the object.
F = \(\frac { { P }_{ 2 }-{ P }_{ 1 } }{ t } \) = \(\frac { 800-500 }{ 6 }\) = \(\frac { 300 }{ 6 }\) = 50 N.

Question 17.
Akhtar, Kiran and Rahul were riding in a motorcar that was moving with a high velocity on an expressway when an insect hit the windshield and got stuck on the windscreen. Akhtar and Kiran started pondering over the situation. Kiran suggested that the insect suffered a greater change in momentum as compared to the change in momentum of the motorcar (because the change in the velocity of the insect was much more than that of the motorcar). Akhtar said that since the motorcar was moving with a larger velocity, it exerted a larger force on the insect And as a result the insect died. Rahul while putting an entirely new explanation said that both the motorcar and the insect experienced the same force and a change in their momentum. Comment on these suggestions.
Answer:
Both, the motorcar and insect experience the equal force and hence, a same change in their momentum. So, we agree with Rahul. But due to smaller mass or inertia, the insect dies.

Question 18.
How much momentum will a dumb – bell of mass 10kg transfer to the floor if it falls from a height of 80cm? Take its downward acceleration to be 10 ms^-2.
Answer:
Here, m = 10kg, u = 0,
s = 80cm = 0.80m,
a = 10 m/s^-2
Let v be the velocity gained by the dumb-bell as it reaches the floor.
As v² – u² = 2as
v² – 0² = 2 × 10 × 0.80 = 16
or
v = 4 ms^-1
Momentum transferred by the dumb-bell to the floor
p = mv = 10 × 4 = 40kg ms^-1

Force and Laws of Motion Additional Questions

Force and Laws of Motion Multiple Choice Questions

Question 1.
Which of the following statements is not correct for an object moving along a straight path in an accelerated motion?
(a) Its speed keeps changing.
(b) Its velocity always changes.
(c) It always goes away from the earth.
(d) A force is always acting on it.
Answer:
(c) It always goes away from the earth.

Question 2.
According to the third law of motion, action and reaction ________ .
(a) Always act on the same body.
(b) Always act on different bodies in opposite directions.
(c) Have same magnitude and directions.
(d) Act on either body at normal to each other.
Answer:
(b) Always act on different bodies in opposite directions.

Question 3.
A goalkeeper in a game of football pulls his hands backwards after holding the ball shot at the goal. This enables the goal keeper to ________ .
(a) Exert larger force on the ball.
(b) Reduce the force exerted by the ball on hands.
(c) Increase the rate of change of momentum.
(d) Decrease the rate of change of momentum.
Answer:
(b) Reduce the force exerted by the ball on hands.

Question 4.
The inertia of an object tends to cause the object ________ .
(a) To increase its speed.
(b) To decrease its speed.
(c) To resist any change in its state of motion.
(d) To decelerate due to friction.
Answer:
(c) To resist any change in its state of motion.

Question 5.
A passenger in a moving train tosses a coin which falls behind him. It means that motion of the train is ________ .
(a) Accelerated
(b) Uniform
(c) Retarded
(d) Along circular tracks.
Answer:
(a) Accelerated

Question 6.
An object of mass 2kg is sliding with a constant velocity of 4 ms^-1 on a frictionless horizontal table. The force required to keep the object moving with the same velocity is ________ .
(a) 32 N
(b) 0 N
(c) 2 N
(d) 8 N.
Answer:
(b) 0 N

Question 7.
Rocket works on the principle of conservation of ________ .
(a) Mass
(b) Energy
(c) Momentum
(d) Velocity.
Answer:
(c) Momentum

Question 8.
A water tanker filled up to \(\frac { 2 }{ 3 }\) of its height is moving with a uniform speed. On sudden application of the brake, the water in the tank would ________ .
(a) Move backward
(b) Move forward
(c) Be unaffected
(d) Rise upwards.
Answer:
(b) Move forward

Question 9.
Which of the following represents example(s) of potential energy?
(a) A moving car
(b) A moving fan
(c) A book resting on the table
(d) Both (a) and (c).
Answer:
(d) Both (a) and (c).

Question 10.
Unit of force is ________ .
(a) Ampere
(b) Volt
(c) Joule
(d) Hertz.
Answer:
(c) Joule

Question 11.
Product of mass and acceleration of a body is called ________ .
(a) Acceleration
(b) Work
(c) Power
(d) Energy.
Answer:
(b) Work

Question 12.
Which of the following is correct about energy?
(a) Energy is not required to do work.
(b) Work can be expressed as Force × Displacement.
(c) Unit of power is joule.
(d) Power is the amount of work done per unit time.
Answer:
(c) Unit of power is joule.

Question 13.
An object of mass 3kg is falling from the height of 1m. The kinetic energy of the body will be when it touches the ground ________ .
(a) 29.4 N
(b) 29.4 J
(c) 30 N
(d) 15 J
Answer:
(b) 29.4 J

Question 14.
Two objects with masses 1kg and 9kg, and equal momentum. Calculate the ratios of their kinetic energies ________ .
(a) 3 : 1
(b) 9 : 1
(c) 1 : 1
(d) 1 : 2
Answer:
(b) 9 : 1

Question 15.
Considering air resistance negligible, the sum of potential and kinetic energies of the free falling body would be ________ .
(a) zero
(b) infinite
(c) would decrease
(d) remains fixed.
Answer:
(d) remains fixed.

Force and Laws of Motion Very Short Answer Type Questions

Question 1.
What do we call to the product of mass and velocity of an object?
Answer:
Momentum.

Question 2.
Define inertia.
Answer:
The property by which an object tends to remain in the state of rest or of uniform motion unless acted upon by some force is called inertia.

Question 3.
Which property has S.I. unit kilogram metres per second i.e., 1kg m/s?
Answer:
Momentum.

Question 4.
Give an example of scalar quantity.
Answer:
Mass.

Question 5.
Give an example of vector quantity.
Answer:
Momentum.

Question 6.
Calculate the total momentum of the bullet and the gun before firing.
Answer:
For both, it would be zero because both of them are at rest.

Question 7.
Which force slows down a moving bicycle when we try to stop?
Answer:
The force of friction.

Question 8.
Which kind of force of gravity work when an object is under free fall?
Answer:
Unbalanced force.

Question 9.
Which property of an object resist a change in their state of rest or motion?
Answer:
Inertia.

Question 10.
Which law of Newton is also known as Galileo’s law of inertia?
Answer:
First law.

Question 11.
Is force a vector quantity?
Answer:
Yes.

Question 12.
Which force of motion opposes motion of an object?
Answer:
Force of friction.

Question 3.
When action and reaction forces act on two different bodies, what kind of magnitude they have?
Answer:
Action and reaction forces act on two different bodies but they are equal in magnitude.

Question 14.
When gun moves in the backward direction, which kind of velocity is generated?
Answer:
Recoil.

Question 15.
Which factor of body is dependent on its mass?
Answer:
Inertia of a body depends on its mass.

Force and Laws of Motion Short Answer Type Questions

Question 1.
There are three solids made up of aluminium, steel and wood, of the same shape and same volume. Which of them would have highest inertia?
Answer:
Steel has highest inertia because it has greatest density and greatest mass, therefore, it has highest inertia.

Question 2.
Two balls of the same size but of different materials, rubber and iron are kept on the smooth floor of a moving train. The brakes are applied suddenly to stop the train. Will the balls start rolling? If so, in which direction? Will they move with the same speed? Give reasons for your answer.
Answer:
If the breaks are applied suddenly then, the balls will start rolling in the direction in which the train was moving. Due to the application of the brakes, the train comes to rest but due to inertia the balls try to remain in motion, therefore, they begin to roll. Direction and speed of all balls will not be same because the masses of the balls are not the same, therefore, the inertial forces are not same on both the balls. Thus, the balls will move with different speeds.

Question 3.
Two identical bullets are fired, one by a light rifle and another by a heavy rifle with the same force. Which rifle will hurt the shoulder more and why?
Answer:
According to law of conservation of momentum or explanation by Newton’s laws of motion, light rifle will hurt the shoulder more.

Question 4.
A horse continues to apply a force in order to move a cart with a constant speed. Explain why?
Answer:
The force applied by the horse balances the force of friction

Question 5.
Suppose a ball of mass m is thrown vertically upward with an initial speed v, its speed decreases continuously till it becomes zero. Thereafter, the ball begins to fall downward and attains the speed v again before striking the ground. It implies that the magnitude of initial and final momentums of the ball are same. Yet, it is not an example of conservation of momentum. Explain.
Answer:
Law of conservation of momentum is applicable to isolated system (no external force is applied). In this case, the change in velocity is due to the gravitational force of earth.

Question 6.
In which of the following conditions work done will be equal to zero?
Answer:
In the absence of any one of the two conditions given below, work done will be equal to zero, that is work is not considered to be executed:

1. Force should act on the object.
2. Object must be displaced.

Question 7.
Define energy and explain its forms.
Answer:

1. Energy: Energy is the capacity of doing work. More the power, more will be energy and vice – versa. For example, a motorcycle has more energy than a bicycle.
2. Forms of energy: There are many forms of energy, such as kinetic energy, potential energy, mechanical energy, chemical energy, electrical energy etc.

Force and Laws of Motion Long Answer Type Questions

Question 1.
Give the formulation of work. In which conditions work can occur?
Answer:
Work = Force × Displacement
or W = F × s
where, W is work ‘F’ is force and ‘s’ is displacement.
If force, F = 0
Therefore, work done, W = 0, s = 0
If displacement, s = 0
Therefore, Work done, W = F × 0 = 0
It proves that, there are two conditions for work to occur or be done:

1. Force should act on the object.
2. Object must be displaced.

Question 2.
Give the conditions when work done become positive and negative.
Answer:
When force is applied in the direction of displacement, the work done is considered as positive.
i.e., W = F × s
When force is applied in opposite direction of displacement, the work done is considered as negative.
i.e., W = -F × s = -Fs.

Question 3.
Explain positive and negative work.
Answer:
1. Positive work:
If a force displaces the object in its direction, then the work done is positive.
Here,
W = Fd
Example:
Motion of ball falling towards ground where displacement of ball is in the direction of force of gravity.

2. Negative work. If the force and the displacement are in opposite directions, then the work is said to be negative.
Here,
W = -Fd.
Example:
If a ball is thrown in upward direction but the force due to earth’s gravity is in the downward direction.

Question 4.
A cyclist moving along a circular path of radius 63m completes three rounds in 3minutes.
1. The total distance covered by him during this time.
2. Net displacement of cyclist.
3. The speed of the cyclist
Answer:
1. Total distance covered
s = 2πr × t
s = 2πr × 3
= 2 × \(\frac { 22 }{ 7 }\) × 63 × 3 = 1188m

2. Displacement = Zero

3. Speed = \(\frac { Distance }{ Time }\)
= \(\frac { 1188 }{ 180 }\)
= 6.6 m/s.

Force and Laws of Motion Higher Order Thinking Skills (HOTS)

Question 1.
As per Newton’s third law, every force is accompanied by equal and opposite force. How then can anything move?
Answer:
According to the Newton’s third law, action and reaction are two equal and opposite forces but they act on different bodies. This make the motion of a body possible.

Question 2.
The passengers travelling in a bus fall ahead when a speeding bus stops suddenly. Why?
Answer:
When the speeding bus stops suddenly lower part of the body, a long with the bus comes to rest while the upper part tends to remain in motion due to inertia of motion. That is why passengers fall ahead.

Question 3.
A player always runs some distance before taking a jump. Why?
Answer:
A player always runs for some distance before taking a jump because inertia of motion helps him to take a longer jump.

Force and Laws of Motion Value Based Question

Question 1.
Sushil saw his karate expert breaking a slate. He tried to break the slate but Sushil’s friend stopped him from doing so and told him that it would hurt, one needs lot of practice in doing such activity.

1. How can a karate expert break the slate without any injury to his hand?
2. What is Newton’s third law of motion?
3. What value of Sushil’s friend is seen in the above case?

Answer:

1. A karate expert Sushil applies the blow with large velocity in a very short interval of time on the slate, therefore large force is exerted on the slate and it breaks.
2. To every action, there is an equal and opposite reaction, both act on different bodies.
3. Sushil’s friend showed the value of being responsible and caring friend.

MP Board Class 9th Science Solutions