A ball A, moving with kinetic energy K,  makes a head on elastic collision with a stationary ball with mass n  times that of A . The maximum potential energy stored in the system during the collision is

Given, K=12mv2 If v'  is the velocity of the balls during collision, then mv+0=(m+nm)v' The maximum potential energy stored during collisions =12mv2−12(m+nm)v'2 =12mv2−12(n+1)mv2(n+1)2 =K−Kn+1           =nKn+1