Two elastic balls of masses M and m `(M gt gt m)` are placed on top of each other with a small gap between them. The balls are dropped on to the ground with the bottom of the lower ball at height h above the ground. The lower ball has a radius R and the upper ball has negligible dimension.

(a) Up to what height the ball of mass m will bounce above the ground ?
(b) Does the result obtained above violates the low of conservation of mechanical energy?

Answer

(a) `2R + 9h`