One particle has a mass of 3.00x10^-3 kg and a charge of +7.80 µC. A second particle has a mass of 6.00x10^-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 3.00x10^-3 kg particle is 130 m/s. Find the initial separation between the particles. Using the information given from the 3x10^-3 kg particle, I tried to use enegry to solve the problem. EPEinitial=EPEfinal+KE I subsituted and eventually ended up with kq^2/r(initial)=kq^2/r(final)+1/2mv^2. I solved the equation for r(final) and I got an answer that made sense, but it was not the right answer. Can anyone tell me what I am doing wrong?