Question

An electron and a positron each have a mass of 9.11*10^-31 kg. They collide and both vanish, with only electromagnetic radiation appearing after the collision. If each particle is moving at a speed of 0.55c relative to the laboratory before the collision, determine the energy of the electromagnetic radiation.

Answer 1

Try E = m c^2 plus the kinetic energy (1/2) mv^2.