CLASS VII- SCIENCE- WORKSHEET - 2 - FORCE AND MOTION- ANSWERS

 WORKSHEET - 2

FORCE AND MOTION

I. Multiple choice questions

1. What is the unit of uniform velocity?

Ans: d. ms-1


2.   Pallavan Express started from Chennai Egmore at 16:00 and reaches Karaikudi at 23:00. The distance covered by this train is 560 km. Calculate its velocity  in kmph.

Ans:a. 80


3. A bowler bowled at a speed of 40 m/s. An Indian cricketer hits the ball, its moves in opposite direction with a speed of 60 m/s. What is the acceleration of the fall if time taken is 10 seconds?

Ans:c. 2m/s2


4. Find out the change in velocity of an object between 20s and 40s.

Displacement in metre

0

10

25

45

60

80

100

120

150

Time in second

0

5

10

15

20

25

30

35

40


Ans:b. 4.5m/s



5. A boy riding a scooter covers a distance of 300m in 15s. What is the speed of the body?

Ans: c. 20m/s


6. An object is thrown upward, it experiences___________.

Ans: d. Non-uniform motion


7. If a body in motion covers equal distance in equal interval of time, then the body is said to be in uniform_______.

Ans: b. Speed


8. In a competition a sprinter starts from rest and achieves a velocity of 30m/s in a time of 6s. What is his average acceleration?

Ans: 5m/s


9. The basic unit of speed is_______.

Ans: d. m/s


10. Some of the students are interested to travel to a tourist spot Mamallapuram from Trichy. Which is about 350km far. They compute their average speed to be 50km/h. How many hours did the trip take?

Ans: b. 7km


11. The total length of a path taken by an object to travel from one place to the other is called______.

Ans: d. distance travelled


II. Fill in the blanks

12. If the velocity of an object decreases with time then the object is said to be in___________.

Ans: negative acceleration.


III. Answer briefly.

13. Complete the table

In the below table the speed of some organism is given. What is the distance covered by them in 100s?

Ans:

Time = 100s

Distance travelled = Speed X Time


Sl. No.

Name of the Organism

Speed 

m/s

Distance

travelled (m)

1

Snail

0.01

1 (0.01 X 100=1)

2

Cheetah

30.00

3000

3

Man

10.00

1000

4

Rabbit

15.00

1500

5

Tortoise

0.08

8


14. A graph is drawn between distance and time. There are two cars A & B are with different acceleration. Which of the two is moving faster? Justify your answer.

Ans:

A is moving faster than B.

Gradient of A is also more than the gradient of B


15. A car starting from rest accelerates uniformly along a straight line. If it attains a velocity of 120kmph in 12s, what is the acceleration of the car in m/s2?

Given:

Velocity v= 120kmph

Time= 12s

Acceleration=?

a=v-u / t

Velocity is in kmph so we have to convert it into m/s

By converting   v= 120km/h into m/s

We will get

=120 X 1000/36000

=33.33m/s

v=33.33m/s

u=0

a = v-u / t

= 33.33 - 0 / 12

= 2.77 m/s2

Acceleration of the car is  2.77 m/s2.


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