Here's the problem: Two particles each have a mass of 6.6x10^-3 kg. One has a charge of +5.0x10^-6 C, and the other has a charge of -5.0x10^-6 C. They are initially held at rest at a distance of 0.70 m apart. Both are then released and accelerate toward each other. How fast is each particle moving when the separation between them is one-half its initial value? I've tried a couple of different ways to attack this, with this one making the most sense to 'me' :rofl: : Knowing both charges and the distance between them, I applied Coulomb's Law to determine a force of .459 (maybe this is my problem? One charge has to remain stationary..?) I then applied this to Newton's F=ma, which would yield an acceleration of 69.49 m/s/s. I finally applied this to Kinematics and found the final velocity after 0.175m (the distance each particle traveled after a combined 0.30 m change in distance). So...where'd it all go wrong? I doubt I'm attacking this the right away, so any thoughts are appreciated :) Thanks.