57. A rubber ball is dropped from a height of 2 metres. To what height will it rise if there is no loss of energy/velocity after rebounding ? A.4 metres B.3 metres C.2 metres D.1 metre
Option C Solution: The potential energy of a body when raised through height h is given by mgh. Each time, a normal rubber ball hits the floor, it loses one-fifth of its total energy and the rebound height is proportional to energy, so each bounce will rebound to four-fifth of the previous bounce. But, the question states that there is no loss of energy/velocity after rebounding. So the height of 2 metres will be maintained.
