1. The problem statement, all variables and given/known data Three positive point charges (with charge and mass given) A (+3q, 2m),B (+q, m) ,C(+4q, 7m/31) can move in a line under the coulomb repelling of one another. The movement begins when all are at rest. Initial distance are (left to right lie A, B, C) AB = r, BC = 2r. Then after they are faraway from one another, what will be their velocities, respectively? (q,m,r are all given.) 2. Relevant equations The coulomb potential energy of q1, q2 displaced r apart, is given by E = kq1 q2/r. 3. The attempt at a solution I notice the energy momentum conservation but this only gives 2 equations in this 1D case. This makes it impossible to solve for 3 velocities. So is it the only way to simulate it in a computer? Or is there any symmetry in it I have missed? I have thought about it for weeks so pls help. Thanks.