Two balls of the same size but different matetials, rubber and iron are kept on the smooth floor of a moving train. The brakers 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 answers.

Explanation

When the train is stopped suddenly, then it comes in the state of rest but the balls remain in the state of motion. So, due to inertia of motion, the balls move in the forward direction. As the balls are of some size but of different material sthat means their mass will be different So, both the balls will move with different speeds.