1. (3 points) An insulator hemispherical shell has radius R and negligible thickness. It carries a uniformly distributed charge Q > 0 and has a total mass M. Another insulator ball has radius r and mass m, and has a uniformly distributed charge q > 0. Initially, the hemispherical shell and the ball are released at the concentric conguration and at zero velocities. The hemispherical shell and the ball then move away from each other due to mutual Coulomb repulsion. See Figure 1. What are the speeds of the hemispherical shell and the ball, respectively, when they reach innity? Figure 1: Coulomb repulsion between a charged hemispherical shell and a charged ball