Two metal spheres, each of mass 10 g and initially at rest, are dropped from a height of 5.0 m in an evacuated chamber. One sphere has a charge of +100 µC, and the other has a charge –100 µC. Find the difference in final speeds of the two spheres (the speeds just before each one hits the ground). Recall that there is an electric field of about 150 V/m near the Earth’s surface.