1. The problem statement, all variables and given/known data Point charge A of mass m for which q=-Q is held in place as point charge B of mass m for which q=+Q is released from rest at a distance x. What is the speed of charge B as it collides with charge a? (This isn't an actual problem we have, just something that I was wondering as we're starting E&M) 2. Relevant equations Fe=kqq/r^2 E=kqq/r Potential energy = Kinetic energy 3. The attempt at a solution I started out with an a(x) equation but didn't get beyond that as I couldn't find how to work with functions of time instead of position. Can you do this by just converting the potential energy at rest to kinetic energy? I feel like there should be more to it because the acceleration goes to infinity as b gets closer and closer to a.