A beam of alpha particles is incident on a target of lead. A particular alpha particle comes in "head-on" to a particular lead nucleus and stops 6.50 x 10-14m away from the center of the nucleus. (This point is well outside the nucleus.) Assume that the lead nucleus, which has 82 protons, remains at rest. The mass of the alpha particle is 6.64 x 10-27 kg.
(a) Calculate the electrostatic potential energy at the instant that the alpha particle stops. Express your result in joules and in MeV.
(b) What initial kinetic energy (in joules and in MeV) did the alpha particle have?
(c) What was the initial speed of the alpha particle?