1. The problem statement, all variables and given/known data A particle of mass 1.00u travelling at speed v, collides with a stationary Cu nucleus of mass 62.93u, and rebounds in the exact opposite direction with a speed of .9687v. What is the recoil velocity of the Cu atom, in terms of v? 2. Relevant equations F=ma P=mv 3. The attempt at a solution If the recoil of the proton is .9687v and the initial velocity was v, then in order to satisfy conservation of momentum, .0313u/v must be transfered to the Cu atom. To solve for velocity of the Cu atom, use p=mv; 0.0313 = 62.93 x v. Therefore v = 0.0005v. Am I correct or just going in the completely wrong direction here?