Forces & Laws of Motion

Which of the following statement is not correct for an object moving along a straight path in an accelerated motion?

• Its speed keeps changing

• Its velocity always changes

• It always goes away from the earth

• A force is always acting on it

A goalkeeper in a game of football pulls his hands backwards after holding the ball shot at the goal. This enables the goal keeper to

• exert larger force on the ball

• reduce the force exerted by the ball on hands

• increase the rate of change of momentum

• decrease the rate of change of momentum

A passenger in a moving train tosses a coin which falls behind him. It means that motion of the train is

• accelerated

• uniform

• retarded

• along circular tracks

An object of mass 2 kg is sliding with a constant velocity of 4 m s^–1 on a frictionless horizontal table. The force required to keep the object moving with the same velocity is

• 32 N

• 0 N

• 10 N

• 2 N

A water tanker filled up to 2 / 3 of its height is moving with a uniform speed. On sudden application of the brake, the water in the tank would

• move backward

• move forward

• be unaffected

• rise upwards

How much net force is required to accelerate a 1000 kg car at 4 m/s²?

• 250 N

• 4000 N

• 0.004 N

• 400 N

If a net force of 5 N was constantly applied on 200 g object at rest, how long will it take to raise its velocity to 150 m/s?

• 2 sec

• 6 sec

• 4 sec

• 8 sec

A sedan car of mass 200kg is moving with a certain velocity. It is brought to rest by the application of brakes, within a distance of 20m when the average resistance being offered to it is 500N.What was the velocity of the motor car?

• 10 m/s

• 20 m/s

• 30 m/s

• 0 m/s

A driver accelerates his car first at the rate of 4 m/s² and then at the rate of 8 m/s² . Calculate the ration of the forces exerted by the engines?

• 4:1

• 1:2

• 2:1

• 1:4

Two objects of masses of 100 gm and 200 gm are moving in along the same line and direction with velocities of 2 ms^-1 and1 ms^-1 respectively. They collide and after collision, the first object moves at a velocity of 4 ms^-1. Determine the velocity of the second object?

• 0 m/s

• 0.5 m/s

• 1 m/s

• 2 m/s