How Does Charge Redistribution Affect Forces in a Triangular Sphere System?

[Shatzkinator]

Homework Statement

In the figure 21-40, three identical conducting spheres form an equilateral triangle of side length d = 24.0 cm. The sphere radii are much smaller than d and the sphere charges are qA = -3.45 nC, qB = -3.91 nC, and qC = +6.09 nC. (a) What is the magnitude of the electrostatic force between spheres A and C? The following steps are taken: A and B are connected by a thin wire and then disconnected; B is grounded by the wire, and the wire is then removed; B and C are connected by the wire and then disconnected. What now are the magnitudes of the electrostatic force (b) between spheres A and C and (c) between spheres B and C?
http://edugen.wiley.com/edugen/courses/crs1650/art/qb/qu/c21/fig21_41.gif

Homework Equations

F = kq1q2/r^2

The Attempt at a Solution

I got 3.28 x 10^-6 N for part A... not sure what to do for B and C

 

[LowlyPion]

... not sure what to do for B and C

Follow the subsequent steps. When A and B are connected what charge ends on each? Then B is rounded so the charge on B is now 0. Now B and C are connected and you end up with how much charge on B and C?

Now it looks like you're back to calculating forces again.