1. The problem statement, all variables and given/known data A snooker ball hits another one of the same mass head-on.If a quarter of the initial kinetic energy is dissipated in the collision ,what is the coefficient of restitution? 2. Relevant equations Ei=Ef 3. The attempt at a solution Energy statement: ua+ub=(3/4)*(Va+Vb) Momentum Conservation: ua+ub=Va+Vb Coefficient of restitution: e=(Vb-Va)/(ua-ub) But i cannot go further i have tried everything to get a result...could you please help me ? The energy statement is wrong but for some reasons i can't put squares on each velocity.