A uranium nucleus (mass 238 u, charge 92e) decays, emitting an alpha particle (mass 4 u, charge 2e) and leaving a thorium nucleus (mass 234 u, charge 90e). At the instant the alpha particle leaves the nucleus, the centers of the two are 5.0fm apart and essentially at rest
Discover their speeds when they're a great distance apart. Treat each particle as a spherical charge distribution.