1. The problem statement, all variables and given/known data An insulating sphere has a radius of 5.00 mm and has a total charge of 4.25 x 10-12 Coulombs, distributed uniformly over its surface. And electron starts from rest at a distance of 9.00mm from the surface and accelerates towards it. How fast in the electron moving when it crashes into the sphere's surface? 2. Relevant equations PEe=(kq1q2)/r W=deltaPEe V(electric potential around point charge)=(kq)/r 3. The attempt at a solution I'm afraid I just don't know where to begin. I've been playing around with these equations but I can't get a velocity to fall out.