MANAV RACHNA INTRNATIONAL SCHOOL, LUDHIANA
SESSION -2025-26
Ch- Force and laws of motion / worksheet 2/ Grade – IX
OBJECTIVE TYPE OF QUESTIONS (1 MARK):
1) Which law of motion explains why passengers inside a moving bus tend to fall backward when the bus
suddenly stops?
a) Newton's First Law
b) Newton's Second Law
c) Newton's Third Law
d) None of the above
2) An object is moving with a constant velocity. Which of the following statements is true?
a) There are no forces acting on the object.
b) The net force acting on the object is zero.
c) The object is not accelerating.
d) All of the above
3) If the mass of an object remains constant and the force acting on it doubles, its acceleration will:
a) Double
b) Halve
c) Remain the same
d) Become zero
4) A block is sliding on a frictionless surface. If a constant force is applied, the block will:
a) Moves with constant speed
b) Slows down and eventually stop
c) Accelerates with a constant acceleration
d) None of the above
5) Which of the following quantities is directly proportional to an object's momentum?
i. Mass
ii. Acceleration
iii. Force
iv. Velocity
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a) i
b) i and ii
c) i and iv
d) iv
6) What is the resultant force?
a) 8 N upwards
b) 12 N downwards
c) 12 N upwards
d) 22 N
7) Why is the reading in the force – meter constant 100 N?
a) Equal forces are acting
b) Unequal forces are acting
c) Equal and opposite forces are acting
d) Unequal and opposite forces are acting
8) Momentum of a body increases from 20kgm/s to 40kgm/s in 5 seconds, then the force applied is
a) -4 N
b) 4 N
c) 20 N
d) -20 N
9) Which law of motion gives the measure of force?
a) Newton’s first law of motion
b) Newton’s second law of motion
c) Newton’s third law of motion
d) Galileo’s law
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?
a) 200 N
b) 100 N
c) 50 N
d) 0 N
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ASSERTION AND REASONING TYPE OF QUESTIONS (1 MARK):
DIRECTION: In the following questions, a statement of assertion (A) is followed by a statement of reason (R).
Mark the correct choice as:
a) Both A and R are true, and R is the correct explanation of A.
b) Both A and R are true, and R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true
11) Assertion: An object can have a non-zero velocity even if the net force acting on it is zero.
Reason: If the object is moving with a constant velocity, the net force acting on it must be zero.
12) Assertion: When an object is thrown vertically upwards, its velocity becomes zero at the highest point
Reason: The object experiences a net force of zero at the highest point.
13) Assertion: While walking on ice, one should take small steps to avoid slipping.
Reason: This is because smaller steps ensure smaller friction.
14) Assertion: Newton’s third law applies to all types of forces. e.g. gravitational, electric or magnetic forces
etc.
Reason: Newton’s third law of motion is applicable only when bodies are in motion.
VERY SHORT ANSWER TYPE OF QUESTIONS: (2 MARK)
15) Why is it advised to tie any luggage kept on the roof of a bus with a rope?
16) Explain how the acceleration of an object is affected by its mass and the applied force, using the second
law equation.
17) If two objects of different masses are subjected to the same force, which one will experience a greater
acceleration? Justify your answer.
18) ‘A boatman pushes the river bank with a bamboo pole to take his boat into the river.’ Explain his action
with reason.
19) In a high jump athletic event, the athletes are made to fall on a cushion bed. Give reason.
20) Why is it incorrect to say that the action-reaction forces cancel each other out? Explain with a suitable
scenario.
21) Why do fielders pull their hand gradually with the moving ball while holding a catch?
22) How does wearing a seatbelt in a moving car relate to Newton's First Law of Motion and the concept of
inertia?
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23) If a body is not at rest, the net external force acting on it cannot be zero. Is it true or false? Justify.
24) A body of mass 2 kg is acted upon by a force of 1 N, what would be its acceleration?
25) What is the momentum of a man of mass 70 kg, when he walks with a uniform velocity of 2 ms-1?
26) How does a swimmer use Newton's Third Law to push against the water and move forward?
27) Water sprinkler, used for grass lawns, begins to rotate as soon as the water is
supplied. Which law of motion is the cause of rotation of the water sprinkler?
Explain.
SHORT ANSWER TYPE OF QUESTIONS (3 MARK):
28) Give reason:
(i) A javelin thrower is marked foul if he crosses over the line marked for throw. Athletes often fail to
stop themselves before the line.
(ii) It is difficult to stop our body, when we accidently step on a peel of banana.
(iii)A stone tied to a string is whirling in a horizontal circle. If the string breaks, the stone flies away
tangentially.
29) A ball of mass 100 g moving with a velocity 10 ms-1 is stopped by a boy in 0.2 s. calculate the force applied
by the boy to stop the ball.
30) When you kick a football it flies away but when you kick a stone you get hurt why?
31) A cart of mass 500 kg is initially at rest. It experiences a constant force for 10 seconds and accelerates
uniformly. Given that the final velocity of the cart is 20 m/s, calculate the magnitude of the force applied.
32) A ball is suspended by a cord from the ceiling of a car. What will be the effect on the position of the ball if (i)
The car is moving with constant velocity? (ii) The car is in accelerated motion? (iii) The car is turning
towards right?
33) Define inertia. How does it depend on mass of the object? Explain (a)Dusting of a carpet by beating it with a
stick. (b)Removal of water from wet cloth.
34) Give reason and give the law related to these statements (a) some of the leaves may get detached from a tree
if we vigorously shake its branch. (b) It is difficult for a fireman to hold a hose which ejects large amount of
water with high velocity.
35) A scooter is moving with a velocity of 20m/s when brakes are applied. The mass of the scooter and the rider
is 180Kg. The constant force applied by the brakes is 500N. a) How long should the brakes be applied to
make the scooter come to a halt? b) How far does the scooter travel before it comes to rest?
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LONG ANSWER TYPE OF QUESTIONS (5 MARK):
36) State the second law of motion and Derive its mathematical expression?
37) Deduce Newton’s first law from the second law.
38) A bullet of mass 4 g when fired with a velocity of 50 ms-1, can enter a wall up to a depth of 10 cm. How
much will be the average resistances offered by the wall?
39) The speed – time graph of a car 1000 kg mass is given below. On the basis of this answer the
following questions.
a) When is the maximum force acting on the car?
b) What is the retarding force acting on the car?
c) For how long is there no force acting on the car?
d) What is the velocity of the car at 5 second?
e) Find the acceleration of the car during the first interval of two second?
CASE STUDY TYPE OF QUESTIONS (4 MARK):
40) Two strings X and Y are tied to the two opposite faces of the block as shown in figure. If we apply a force
by pulling the string X, the block begins to move to the right. Similarly, if we pull the string Y, the block
moves to the left. But, if the block is pulled from both the sides with equal forces, the block will not move.
Such forces are called balanced forces and do not change the state of rest or of motion of an object. Now, let
us consider a situation in which two opposite forces of different magnitudes pull the block. In this case, the
block would begin to move in the direction of the greater force. Thus, the two forces are not balanced and the
unbalanced force acts in the direction the block moves. This suggests that an unbalanced force acting on an
object brings it in motion. Force is push or pull.
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(i) What happens when a balanced force is acting on a moving object?
(ii) From above diagram if one person pulls from Y rope with 10N force and another person pull
from X rope with 5N force, what is the net force acting on the box?
(iii) Differentiate between balanced and unbalanced force
OR
A speedboat has a mass of 500 kg. It starts from rest and travels 200 m in 12 s. The boat
undergoes constant acceleration during 12 s. Find the magnitude of unbalanced force acting on the
boat?
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