Electric potential energy - how is it conserved??? obviously the answer is yes , its conserved.. but something bugs me about it. One particle has a mass of 3.00×10–3 kg and a charge of +8.00 mC. A second particle has a mass of 6.00×10–3 kg and the same charge. The two particles are initially held in place and then released. The particles fly apart, and when the separation between them is 0.100 m, the speed of the 3.00×10–3-kg particle is 125 m/s. Find the initial separation between the particles. Am i doing this correctly? Ebefore = Eafter kq1q2/r = kq1q2/(r+0.1) + m1v1^2/2 is this correct? if so, does that mean (according the the equation) all the energy is in the 1st particle.. then the other one should be stationary? obviously not.. then why is my equation wrong? what am i missing? should it be kq1q2/r = kq1q2/(r+0.1) + m1v1^2/2 + m2v2^2/2 ? but now how can u solve for 2 unknowns? (r and v2) would you use m1v1 = m2v2 to solve for v2? why (if u can) can u use this?