1. The problem statement, all variables and given/known data Two particles, A, of mass 2M, and B, of mass M , whilst moving on a smooth horizontal table in opposite directions with speeds of 5v and 3v respectively, collide directly. Find their velocities after the collision in terms of v and the coefficient of restitution e. 3. The attempt at a solution Since I am not given the co-efficient of restitution. It seems that all I have is the conservation of momentum equation. An equation with 2 unknowns, how is it possible to get the velocities in terms of v?