JEE Physics Force and Laws of Motion MCQs Set B

Question. An external influence which changes or tends to change the state of rest or uniform motion of body or its dimensions is called :
(a) momentum
(b) force
(c) moment of force 
(d) pressure

Answer : B

Question. Equal and opposite forces acting on a body which do not change its state of rest or uniform motion are called:
(a) like parallel forces
(b) unlike parallel forces
(c) balanced forces
(d) all the above

Answer : C

Question. The unequal and opposite forces acting on a body, which change its state of rest or uniform motion are called:
(a) unbalanced forces
(b) balanced forces
(c) like parallel forces 
(d) all the above

Answer : A

Question. Force of friction always acts in the direction:
(a) of applied force
(b) opposite to the direction of applied force
(c) at right angles to the direction of applied force
(d) none of the above

Answer : B

Question. When balanced forces act on a body, the body:
(a) must remain in its state of rest
(b) must continue moving with uniform velocity, if already in motion
(c) must experience some acceleration
(d) both (a) and (b)

Answer : D

Question. When unbalanced forces act on a body, the body:
(a) must move with uniform velocity
(b) must remain at rest
(c) must experience acceleration
(d) must move in a curved path

Answer : C

Question. If no external force acts on a body, it will :
(a) move with more speed
(b) change its shape
(c) break into pieces
(d) either remain in its state of rest or in uniform motion.

Answer : D

Question. If a body is allowed ti freely fall from a height, its speed increases continuously. It is because:
(a) air does not exert frictional force
(b) magnetic force of earth increases its speed
(c) gravitational force of earth increases its speed
(d) pressure of air forces it downward

Answer : C

Question. A force of magnitude' F' acts on a body of mass 'm'. The acceleration of the body depends upon:
(a) volume of body 
(b) density of body
(c) area of body
(d) mass of body

Answer : D

Question. Force remaining constant, if the mass of body increases, its acceleration is likely to :
(a) increase
(b) remain same
(c) decrease
(d) sometimes increases and sometimes decreases

Answer : C

Question. A force F produces an acceleration 'a' in a body. The same force produces and acceleration 4a in another body. The mass of other body is :
(a) four times the mass of first body
(b) four times less the mass of other body
(c) mass does not play role
(d) none of the above

Answer : B

Question. When a running motorbike accelerates suddenly, the pillion rider has a tendency to fall backward. This is an example of:
(a) Newton's first law of motion
(8) Newton's second law of motion
(c) Newton's third law of motion
(d) Newton's law of gravitation of motion

Answer : A

Question. Which is the incorrect statement? A spaceship continues moving in space with uniform speed because:
(a) no force of friction due to air acts on it
(b) its mass is zero in space
(c) no force of gravitation acts on it
(d) no force of friction due to earth acts on it

Answer : B

Question. The impact which a body can produce due to the combined effect of mass and velocity is called:
(a) momentum
(b) force
(c) moment of force
 (d) pressure

Answer : A

Question. The SI unit of momentum is :
(a) newton 
(b) newton-second
(c) dyne
(d) dyne-second

Answer : B

Question. The tendency of a body to continue in its state of rest or uniform motion, even on the application of external force is called:
(a) force 
(b) momentum
(c) inertia
(d) impulse

Answer : C

Question. A body will continue in its state of rest or uniform motion in a straight line, unless acted by some external force. The statement represents :
(a) Newton's second law of motion
(b) Newton's first law of motion
(c) Newton's third law of motion
(d) Law of conservation of momentum

Answer : B

Question. The magnitude of inertia of a body is determined by its:
(a) mass
(b) weight
(c) velocity
(d) acceleration

Answer : A

Question. Momentum is a:
(a) vector quantity
(b) scalar quantity
(c) fundamental quantity
(d) none of the above

Answer : A

Question. A body P has mass 2 m and velocity 5 v. Another body Q has mass 8 m and velocity 1.25 v. The ratio of momentum of P and Q is :
(a) 2 : 1
(b) 1 : 1
(c) 1 : 2 
(d) 3 : 2

Answer : B

Question. The magnitude of a physical quantity is 8.5 Ns. The physical quantity is :
(a) force 
(b) momentum
(c) pressure
(d) moment of force

Answer : B

Question. There is a rubber ball and a stone ball of same size. If both balls are at rest:
(a) rubber ball has more inertia than stone ball
(b) stone ball has more inertia than rubber ball
(c) both have same inertia
(d) none of the above.

Answer : B

Question. When we vigorously a shake branch of a tree, some leaves get detached. It is due to the:
(a) inertia of rest
(b) inertia of motion
(c) some leaves are loosely held by the branch
(d) none of the above.

Answer : A

Question. When the driver of a fast moving car suddenly applies brakes, the passengers in the car:
(a) fall backward 
(b) fall forward
(c) are not affected
(d) none of the above.

Answer : B

Question. A batsman hits a cricket ball, which then rolls on a level ground. After covering a short distance, the ball comes to rest. The ball slows down to stop because:
(a) the batsman did not hit the ball hard
(b) velocity of ball is proportional to force acting on it
(c) there is force on the ball opposing its motion
(d) there is no unbalanced force on the ball and hence it comes to rest

Answer : C

Question. The force of freely falling body is directly proportional to:
(a) mass of body
(b) acceleration of body
(c) velocity of body
(d) both (a) and (b)

Answer : D

Question. The principle of conservation of linear momentum states that in a system it
(a) cannot be changed
(b) can be changed, if internal forces act on it
(c) can be changed, if external forces act on it
(d) none of the above

Answer : A

Question. Action-reaction forces:
(a) act on same body
(b) act on different bodies
(c) act along different lines
(d) act in same direction

Answer : B

Question. A porter is carrying a weight of 200 N on his head. If the force exerted on his head is taken as action, then the reaction force is exerted by :
(a) the head on the weight
(b) the weight on the earth
(c) the earth on the porter
(d) the earth on the weight

Answer : C

Question. Which of the following are vector quantities:
(a) momentum 
(b) velocity
(c) force 
(d) all of the above.

Answer : D

Question. Two bodies collide at the same time. Which of the following is conserved?
(a) velocity 
(b) kinetic energy
(c) momentum 
(d) force

Answer : C

Question. Impulse is equal to :
(a) the change in force
(b) the change in momentum
(c) the change in velocity
(d) all the above

Answer : B

Question. A rocket works on the principle of:
(a) conservation of energy
(b) conservation of linear momentum
(c) conservation of inertia
(d) conservation of force

Answer : B

Question. When a speeding car takes a sharp turn, the persons sitting in it experience outward pull. This happens due to:
(a) inertia of direction
(b) change in momentum
(c) change in acceleration
(d) none of the above

Answer : A

Question. The ratio of force and acceleration of a moving body is the measure of its:
(a) velocity
(b) momentum
(c) mass
(d) impulse

Answer : C

Question. When you kick a stone, you get hurt. Due to which property this happens?
(a) inertia of stone
(b) velocity of the kick
(c) momentum of the kick
(d) reaction of the stone

Answer : D

Question. A motor bike accelerates on the horizontal road due to the force exerted by :
(a) the engine of motorbike
(b) the earth
(c) the driver on the motorbike
(d) none of the above.

Answer : B

Question. Impulse has same unit as that of:
(a) force 
(b) pressure
(c) momentum 
(d) moment of force

Answer : C

Question. By Newton's second law, the physical quantity which can be calculated, if we know the magnitude of force on a given mass is :
(a) velocity
(b) acceleration
(c) momentum
(d) none of the above.

Answer : B

Question. A body is moving with a constant momentum. The motion of the body is :
(a) uniform velocity
(b) accelerated
(c) de-accelerated
(d) none of the above.

Answer : D

Question. A cracker at rest explodes into two equal parts. These parts will move in :
(a) opposite direction with different velocities
(b) same direction with different velocities
(c) same direction with same velocities
(d) opposite direction with same velocities

Answer : D

Question. A batsman has a choice to use heavy or light bat, while facing a fast bowler. He will prefer:
(a) light bat, because handling it is easy
(b) heavy bat, so that he can handle it firmly
(c) heavy bat, because it will recoilless
(d) none of the above.

Answer : C

Question. A vehicle has a mass of 1500 kg. If the vehicle is to be stopped with a negative acceleration of 1.7 ms–2, the force of friction between the vehicle and road is :
(a) –2250 N 
(b) –2050 N
(c) –2550 N 
(d) none of the above.

Answer : C

Question. A man while running at a constant acceleration of 3.5 ms–2, develops a force of 280 N. The mass of man is:
(a) 80 kg 
(b) 85 kg
(c) 75 kg 
(d) 60 kg

Answer : A