A steel sphere A is at rest on a frictionless horizontal surface. Another identical sphere B moving with velocity 2m/s collides head on with A. If coefficient of restitution e = 0.5, fraction of kinetic energy of B lost in the process is

Conserving momentum: mv= mv1+mv2 where v1 is the final velocity of B while v2 is the final velocity of Av2-v1= v2Putting above value in first equation, we getv2=3v1v1=v4 v2=3v4   Change in kinetic energy of B = 1532mv2Thus fraction of KE lost= 1516