I have attempted this problem twice and have one more chance before I get the "red ex" so I thought I'd check my thinking. Two identical conducting spheres, fixed in place, attract each other with an electrostatic force of 0.136 N when their center-to-center separation is 65.0 cm. The spheres are then connected by a thin conducting wire. When the wire is removed, the spheres repel each other with an electrostatic force of 0.0477 N. Of the initial charges on the spheres, with a positive net charge, what was (a) the negative charge in coulombs on one of them and (b) the positive charge in coulombs on the other? To find q I used Coulomb's equation, solving for q, which is the charge on the spheres after they touch. That was q= 1.497E-6 C. Then I thought that F=k Q(Q+2q)/r^2 but that made for some hairy quadratic action trying to get Q and Q+2. Plus they said my answers were wrong twice. For this one I got Q = 1.05E-6 C and then the other (+) ball would be 6.11E-6 C. Is my thinking anywhere in the ballpark? I'm not so sure on the second part.