Q. Three equal 1.45- point charges are placed at the corners of an equilateral triangle whose sides are 0.700 long. What is the potential energy of the system? (Take as zero the potential energy of the three charges when they are infinitely far apart.)

Q. A uranium nucleus (mass 238 , charge 92) decays, emitting an alpha particle (mass 4 , charge 2) and leaving a thorium nucleus (mass 234 , charge 90). At the instant the alpha particle leaves the nucleus, the centers of the two are 7.5 apart and essentially at rest.Find their speeds when they're a great distance apart. Treat each particle as a spherical charge distribution.