Alright, new idea: would it be easier instead to find the time it takes for a positive charge to collide with a negative charge that is held in place a distance r away from where the positive charge starts?
It's probably easier to find the time it takes the moving charge to move from r to r-x...
Just gave it some more thought and realized the U -> KE idea doesn't make sense (U increases as x decreases)... can anyone point me in the right direction?
Homework Statement
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...