A car is moving with a uniform velocity of 30 m s^-1. It is stopped in 2 s by applying a force of 1500 N through it's brakes. Calculate (a) the change in momentum of car, (b) the retardation produced in car, and (c) the mass of the car.

A bullet of mass 50 g moving with an initial velocity of 100 m s^-1, strikes a wooden block and comes to rest after penetrating a distance 2 cm in it. Calculate (i) initial momentum of the bullet (ii) final momentum of the bullet, (iii) retardation caused by the wooden block, and (iv) resistive force exerted by the wooden block

Which law of motion explains how a force acts on a body or an object?

1. Newton's third law
2. Newton's second law
3. Newton's first law
4. All of the above.

To every action there is always :

1. an equal reaction
2. an equal and opposite reaction
3. an equal reaction in the same direction
4. none of these