Ive got this one homework problem that i am totally clueless on. Any help? "Two insulating spheres having radii 0.34 cm and 0.54 cm, masses 0.13kg and 0.58 kg, and charges -3x10^-6 C and 2x10^-6 C are released from rest when their centers are seperated by 1.2m. How fast is the smaller sphere moving when they collide? Answer in units m/s."