# Worksheet on Force , Momentum & Laws of Motion

Given below are the force and laws of motion class 9 worksheet
(a) Objective Type Questions
(b) Very Short questions
(c) Short questions
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## Multiple Choice questions

Question 1
Which is true from Newton's Third law of motion?
a. For every action force there is a 50% reaction force in the opposite direction.
b. For every action force there is an equivalent reaction force in the opposite direction.
c. Both 1 and 2
d. None of the above

Question 2
In the equation $F = ma$, what does m represent?
(a) Mass
(b) Meters
(c) Force
(d) Acceleration

Question 3
Newton's First Law of Motion is also called:
a. Law of Friction
b. Law of Reaction
c. Law of Action
d. Law of Inertia

## Very Short Questions Type

Question 1.
During the game of table tennis, if the ball hits a player it does not hurt him. On the other hand when a fast moving cricket ball hits a spectator it may hurt him. State reason.

Question 2.
Define the first law of motion
Question 3
Why do a back seater moves forward when a fast moving bike is stopped suddenly?

Question 4.
When a carpet is beaten with a stick it releases dust. Explain why.

Question 5.
Name the physical quantity that measures inertia. State its SI unit.

Question 6.
Name the property of bodies by virtue of which they resist a change in their state of rest or of uniform motion.

Question 7.
What is the momentum of a body of mass 5 kg moving with a velocity of 0.20 m/s.

Question 8.
Write the net force acting on a bus, of mass 2000 kg, moving with a uniform velocity of 60 km/h.

Question 9.
State the relation between the momentum of a body and the force acting on it.

Question 10.
A body of mass 25 kg has a momentum of 125 kg m/s. calculate the velocity of the body.

Question 11.
Name the physical quantity which is measured/ determined by the rate of change of momentum.

Question 12.
What is the mathematical formula and SI unit of momentum?

Question 13.
What force would be needed to produce an acceleration of 4 m/s2 on a ball of mass 6 kg?

Question 14.
State Newton’s third law of motion.
Question 15.
In the collision between a heavier body and a lighter body, if the force experienced by the heavier body is $F_1$ and that by the lighter body is $F_2$, write the relation between $F_1$ and $F_2$.

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?

Question 2.
Two friends on roller – skates are standing 5 m apart facing each other. One of them throws a ball of 2 kg towards the other, who catches it. How will this activity affect the position of the two? Explain your answer.

Question 3.
Give reason and give the law related to these statements:
(a) It is easier to push an empty box than to push the box full of books.
(b) It is difficult for a fireman to hold a hose which ejects large amount of water with high velocity.

Question 4.
(a) Name the force that keeps the object moving in a circular path with constant acceleration.
(b) What would happen if this force is absent?

Question 5.
It is necessary to run along with the moving bus in the same direction of the bus, while alighting from the bus. Give reasons.

Question 6.
Which of the following has more inertia? Give reason for your answer:
(i) A bicycle and a train
(ii) A rubber ball and a stone of the size.
(iii) A five rupee coin and a one rupee coin.
(iv) A bicycle or a truck.

Question 7.
Find the change in momentum of a car weighing 1500 kg when its speed increases from 36 km/h to 72 km/h.

Question 8.
Two objects A and B of same masses and velocity V and 3 V respectively are in motion.
(a) Which object will have larger momentum?

Question 9.
While playing football, the goalkeeper did not get sufficient time to stop a fast ball shot towards him. Why did he hurt his hand while doing so?
Question 10.
The hand gets hurt while punching a wall. Why?
Question 11.
(i) Explain why is it difficult for a fireman to hold a hose, which ejects a large amount of water at a high velocity.
(ii) Why action and reaction do not cancel each other?

Question 12.
From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m/s. Calculate the initial recoil velocity of the rifle.

Question 13.
An object of mass 1 kg travelling in a straight line with a velocity of 10 m/s collides with, and sticks to a stationary wooden block of mass 5 kg. 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.

Question 14
What is the difference between balanced force and unbalanced force?

Question 15
State the various effects of force?

Question 16
Give reason for each of these

Question 16.
(i)State the law of conservation of momentum.
(ii(Using this law explain why a gun recoils.
Question 17.
A stone released from the top of a tower of height 19.6 m, calculate its final velocity just before touching the ground. (Take g = 9.8 m/s2)

Question 18.
A boy of mass 50 kg running 5 m/s jumps on to a 20 kg trolley travelling in the same direction at 1.5 m/s. find their common velocity.

Question 19.
Car A of mass 1500 kg travelling at 25 m/s collides with another car B of mass 1000 kg travelling at 15 m/s in the same direction. After collision, the velocity of car A becomes 20 m/s. Calculate the velocity of car B after collision.

## Summary

This Worksheet on Force , Momentum & Laws of Motion Class 9 physics is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.