Hi again guys. I've got a test charge place a certain distance away from a large flat uniformly charged non-conducting surface. I'm told what the force charge is from this distance. Then the test charge is moved, and I'm supposed to say what the force on the test charge is now. I tried doing it the way I'd handle two charges,: E = (K*q1*q2)/r^2 solving for q2 and then changing the distance, but that didn't work. So I'm a bit lost. A lil' help please? Edit: I'm told what the charge of the test charge is. Just in case.