The text showed that the attractive force F between an origin-centered, grounded, conducting sphere of radius R and a point charge located at a point s > R on the positive z-axis varies as 1/s³ when s >> R. Replace the sphere by a grounded conductor of any shape. Use Green’s reciprocity principle to show that the force between the conductor and the charge still varies as 1/s³ when s is large compared to the characteristic size of the conductor.