Source: Exemplar
Two balls of the 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?
Options
Option A
No, the balls will remain stationary.
Option B
Yes, the balls will roll forward with the same speed.
Option C
Yes, the balls will roll backward with the same speed.
Option D is correct
Yes, the balls will roll backward, but with different speeds.