CBSE Class 11 Physics Laws of Motion MCQs

Question: Newton's first law of motion describes the

a) inertia

b) energy

c) work

d) moment of inertia

Answer: inertia

Question: Inertia is the property of a body linked to tendency of a body

a) to resist any change in its state

b) to change the momentum

c) to change its direction

d) to change its position

Answer: to resist any change in its state

Question: Physical independence of force is a consequence of

a) first law of motion

b) third law of motion

c) second law of motion

d) all of these

Answer: first law of motion

Question: A reference frame attached to the earth

a) cannot be an inertial frame because earth is revolving round the sun

b) is an inertial frame by definition

c) is an inertial frame because Newton's laws are applicable

d) is an inertial frame because the earth is rotating about its own axis

Answer: cannot be an inertial frame because earth is revolving round the sun

Question: The direction of impulse is

a) same as that of the net force

b) opposite to that of the net force

c) same as that of the final velocity

d) same as that of the initial velocity

Answer: same as that of the net force

Question: When a body is stationary

a) the combination of forces acting on it balances each other

b) the body is in vacuum

c) the force acting on it is not in contact with it

d) there is no force acting on it

Answer: the combination of forces acting on it balances each other

Question: When an elevator cabin falls down, the cabin and all the bodies fixed in the cabin are accelerated with respect to

a) man standing on earth

b) ceiling of elevator

c) floor of elevator

d) man standing in the cabin

Answer: man standing on earth

Question: A monkey is climbing up a rope, then the tension in the rope

a) must be equal to the force applied by the monkey on the rope

b) must be less than the force applied by the monkey on the rope.

c) must be greater than the force applied by the monkey on the rope.

d) may be equal to, less than or greater the force applied by the monkey on the rope.

Answer: must be equal to the force applied by the monkey on the rope

Question: If two masses (M & m) are connected on a horizontal plane and a force is applied on the combination, then the tension T depends on

a) whether force is applied on M or m

b) the force applied on the system

c) Can’t be predicted.

d) None of these

Answer: whether force is applied on M or m

Question: A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring reads 49 N, when the lift is stationary. If the lift moves downward with an acceleration of 5 m/s², the reading of the spring balance will be

a) 24 N

b) 74 N

c) 15 N

d) 49 N

a) Friction does not depend on the area in contact

b) Friction is always less than the applied force

c) Friction depends on the volume of body

d) Friction depends on the area of contact.

Answer: Friction does not depend on the area in contact

Question: The coefficient of static friction between two surfaces depends upon

a) the normal reaction

b) the shape of the surface in contact

c) the magnitude of applied force

d) None of these

Answer: the normal reaction

Question: If the applied force is doubled, then coefficient of friction is

a) not changed

b) tripled

c) halved

d) doubled

Answer: not changed

Question: Which of the following statements about friction is true?

a) Kinetic friction is always greater than rolling friction

b) Frictional force is proportional to the area of contact between the two surfaces

c) Frictional force cannot accelerate a body

d) Friction can be reduced to zero

Answer: Kinetic friction is always greater than rolling friction

Question: A block of mass 0.1kg is held against a wall applying a horizontal force of 5 N on the block. If the coefficient of friction between the block and the wall is 0.5, the magnitude of the frictional force acting on the block is:

a) 0.98 N

b) 4.9 N

c) 0.49 N

d) 2.5 N

Answer: 0.98 N

Question: What are the effects if force is acting on a moving body in a direction perpendicular to the direction of motion

a) The direction of motion changes

b) All of these

c) The acceleration changes uniformly

d) The speed changes uniformly

Answer: The direction of motion changes

Question: On a banked road, which force is essential to provide the necessary centripetal force to a car to take a turn while driving at the optimum speed?

a) Component of normal reaction

b) Component of frictional force

c) Both

d) None of these

Answer: Component of normal reaction

Question: A cyclist taking turn bends inwards while a car passenger taking the same turn is thrown outwards. The reason is

a) cyclist has to counteract the centrifugal force while in the case of car only the passenger is thrown by this force

b) difference in the speed of the two

c) car has four wheels while cycle has only two

d) car is heavier than cycle

Answer: cyclist has to counteract the centrifugal force while in the case of car only the passenger is thrown by this force

Question: A cyclist bends while taking turn in order to

a) provide required centripetal force

b) reduce apparent weight

c) reduce speed

d) reduce friction

Answer: provide required centripetal force

Question: A car moving on a horizontal road may be thrown out of the road in taking a turn

a) due to the lack of proper centripetal force

b) due to the rolling frictional force between the tyre and road

c) due to the reaction of the ground

d) by the gravitational force

Answer: due to the lack of proper centripetal force