1. The problem statement, all variables and given/known data I am basically wondering how they got to the assumption that the Ve = 2Vα. I've tried it a few times and I keep on getting that based off of their other assumptions, Ve should =0, even though I know that this cannot possibly be the case. 2. Relevant equations Conservation of momentum: Mava = Mav'a + meve Conservation of energy: .5Mava2 = .5Mav'a2 + .5Meve2 3. The attempt at a solution I really don't know what to do. I've tried starting under the assumption as given that Va≈Va', which leads to getting Ve=0. I tried to do a binomial expansion using the fact that Me<<Ma, but again I got zero. I'm really not sure how to approach this. Any help would be appreciated.