Hi all, I need help on the following problem: A solid spherical conductor S contains 2 small spherical cavities (not-concentric). The total charge on the conductor is zero, but at the center of each cavity there are two point charges q1 and q2 respectively. At large distance r away from the center of the sphere, there is a third charge Q. What force exists on each of the four objects in this problem: Q, S, q1, and q2? Which answers, if any, are approximate and depend on r being relatively large? Thanks.