posted by Abby .
A photon of energy E strikes an electron at rest undergoes pair production, producing a positive electron(positron) and an electron,
photon+electron produce positron+electron+electron
The two electrons and the positron move off with identical momenta in the direction of the initial photon. Find the kinetic energy of the three final particles and find the energy E of the photon(Hint: conserve momentum and relativistic energy)