1. The problem statement, all variables and given/known data Two identical + 8.5mu C point charges are initially 2.5 cm from each other. If they are released at the same instant from rest, how fast will each be moving when they are very far away from each other? Assume they have identical masses of 2.0mg . 2. Relevant equations ΔKE + ΔPE = 0 ΔPE = qV 3. The attempt at a solution I went to a tutoring session today and the tutor told me ΔPE = -kq^2/r. I have no idea from where this derivation came. I'm looking at my book right now and it says ΔPE = qV. Also, she said since there are two balls ΔKE = mv^2 as opposed to 1/2mv^2, which I understand. If I'm going to use ΔPE = qV, I'm unsure how to find the electric potential difference.