Two particles, with charges of 20 nC and -20nC, are placed at the points with coordinates (0, 4 cm) and (0, -4 cm). A particle with charge 10 nC is located at the origin.
(a) Find the electric potential energy of the configuration of the three fixed charges.
(b) A fourth particle, with a mass of 2.00*10^-13 kg and a charge of 40 nC is released from rest at the point (3 cm, 0). Find its speed after it has moved freely to a very large distance away.