Laws of Motion Class 9 Chapter 1 MCQ

 

 Laws of Motion Class 9 Chapter 1 MCQ
Maharashtra state Board
Class: 9 MCQ

1	Which of the following statements is not correct for an object moving along a straight path in an acceleration 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
ANS	A force is always acting on it

 

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
ANS	Always act on different bodies in opposite direction

 

3	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
ANS	To resist any change in its state of motion

 

4	A passenger in a moving train tosses a coin which falls behind him. It means that motion of the train is?
A	Acceleration
B	Uniform
C	Retarded
D	Along circular tracks
ANS	Acceleration

 

5	An object of mass 2 kg 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
ANS	0 N

 

6	Rocket works on the principle of conservation of?
A	Mass
B	Energy
C	Momentum
D	Velocity
ANS	Momentum

 

7	A water tanker filled up to  of its height is moving with a uniform speed. On a sudden application of brakes, the water in the tank would?
A	Move backward
B	Move forward
C	Be unaffected
D	Rise upwards
ANS	Move forward

8	If the mass of a body is doubled and its velocity becomes half, then the linear momentum of the body will?
A	Remain same
B	Become double
C	Become half
D	Become four times
ANS	Remain same

 

9	When a number of forces acting simultaneously on a body bring about a change in its state of rest or of uniform motion in a straight line, then these forces acting on the body are said to be?
A	Balanced forces
B	Equal forces
C	Unbalanced forces
D	Opposite forces
ANS	Opposite forces

 

10	When a car at high speed makes a sharp turn, the driver in a car tends to get thrown to the side opposite to the turn. This is due to the?
A	Inertia of motion
B	Inertia of time
C	Inertia of rest
D	Inertia of direction
ANS	Inertia of motion

  

11	A man is standing on a boat in still water. If he walks towards the shore, then the boat will?
A	Move away from the shore
B	Move towards the shore
C	Remain stationary
D	None of these
ANS	Move away from the shore

 

12	Which of the following is an incorrect statement?
A	Mass is measure of inertia of a body
B	Newton’s first law of motion is the law of inertia
C	Unbalanced force produces constant velocity
D	Newton’s third law talks about the direction of the force
ANS	Unbalanced force produces constant velocity

 

13	A ball is thrown vertically upward in a train moving with uniform velocity. The ball will?
A	Fall behind the thrower
B	Fall ahead of the thrower
C	Return back to the thrower
D	Fall on the left of the thrower
ANS	Return back to the thrower

 

14	Which of the following is not an application of conservation of liner momentum?
A	While firing a bullet, the gun must be held tight to the shoulder
B	When a man jumps from a boat to the shore
C	A rocket explodes on midway from the ground
D	A body suspended from the hook of a spring balanced in a lift which is accelerated downward
ANS	A rocket explodes on midway from the ground

 

15	When we stop pedaling, the bicycle begins to slow down. This is because of the?
A	Frictional force acting along the direction of motion of bicycle
B	Air resistance which is in the direction of motion
C	Frictional force acting opposite to the direction of motion of bicycle by the road
D	Nature of the bicycle to stop after some time
ANS	Nature of the bicycle to stop after some time

 

16	Inertia is the property of a body by virtue of which, it cannot change by itself?
A	Its state of rest
B	Its steady state of uniform motion
C	Its direction of motion
D	All of these
ANS	All of these

 

17	A bullet of mass A and velocity B is fired into a wooden block of mass C. If the bullet gets embedded in the wooden block, then the magnitude of velocity of the system just after the collision will be?
A
B
C
D
ANS

 

18	The masses of two bodies are in ratio 5:6 and their velocities are in ratio 1:2. Then their liner momentum will be in the ratio?
A	5:6
B	1:2
C	12:5
D	5:12
ANS	5:12

 

19	Qualitative definition of force is given by?
A	Newton’s first law of motion
B	Newton’s second law of motion
C	Newton’s third law of motion
D	Newton’s law of gravitation
ANS	Newton’s first law of motion

 

20	Formula to find the force is?
A	F = ma
B	F = m/a
C	F = a/m
D	A = fm
ANS	F = ma

 

21	A plate, a ball and a child all have the same mass. The one having more inertia is the?
A	Plate
B	ball
C	Child
D	All have equal inertia
ANS	All have equal inertia

 

22	The S.I unit of force is?
A	Newton  - meter
B	Newton
C	Newton per second
D	Newton per square meter
ANS	Newton

 

23	Rate of change of momentum is equal to?
A	Acceleration
B	Work done
C	Force
D	Impulse
ANS	force

 

24	When a force is exerted on an object, it can change its?
A	State
B	Position
C	Shape
D	All the above
ANS	All the above

 

25	Acceleration acts always in the direction …….?
A	Of the displacement
B	Of the initial velocity
C	Of the net force
D	Of the final velocity
ANS	Of the net force

 

26	Friction is?
A	Useful to us
B	Harmful to us
C	Both useful as well as harmful to us
D	None of them
ANS	Both useful as well as harmful to us

 

27	When no external force acts on an object, the physical quantity that remains conserved is …….?
A	Velocity
B	Momentum
C	Acceleration
D	Force
ANS	Momentum

 

28	A unit of force is?
A	Joule - m
B	Joule
C	Newton -m
D	Kg ms -2
ANS	Kg ms -2

 

29	……. Is a force, which always opposes the motion of one body over the other body in contact with it?
A	Gravitational force
B	Reaction force
C	Normal force
D	Frictional force
ANS	Frictional force

 

30	Under which of the following conditions, van der waal’s gas approaches ideal behaviour?
A	Extremely low pressure
B	High pressure
C	Low product of pv
D	Low temperature
ANS	Extremely low pressure