Question

Explain the meaning of inertia with the help of an example.

Two balls of same size but of different materials, rubber and iron are kept on the smooth floor of a moving train. The brakes are applied suddenly to stop the train. Will the balls start rolling? If so, in which direction? Will they move with the same speed? Give reasons for your answer.

A ball of mass m is thrown vertically upward from the ground with an initial speed v, its speed decreases continuously till it becomes zero. Thereafter, the ball begins to fall downward and attains the speed v again before striking the ground. It implies that the magnitude of initial and final momentum of the ball are same. Yet, it is not an example of conservation of momentum. Explain why?

A bullet of mass 20 g is horizontally fired with a velocity 150 m s⁻¹ from a pistol of mass 2 kg. What is the recoil velocity of the pistol?