A rubber ball is dropped from a height of 5 m on a planet where the acceleration due to gravity is not known. On bouncing, it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of

If ball falls from height h1  and bounces back up to height h2  then  e=h2h1Similarly if the velocity of ball before and after collision are v1 and v2 respectively then e=v2v1So v2v1=h2h1=1.85=925=35i.e. fractional loss in velocity=1−v2v1=1−35=25