1. The problem statement, all variables and given/known data photon collides with an electron producing a electron-positron pair, the three particles ( two electrons and one positron) move together in the same direction of the original photon. calculate the energy of each particle. 2. Relevant equations photon: Ep=hf p=E/c electron/positron 1) E=Ke+me*c^2 3. The attempt at a solution so 2)Ep + me*c^2=3E : photon energy plus electron rest energy equals the energy of the 3 remaining particles and since mass and direction is the same the energy is the same, same goes for momentum 3)Ep/c=3p so 2 equations 3 unkowns so i wrote eq 2) with 1) and substituted k for 1/2*me*v^2 and in eq 3) i substituted p for me*v, this did not yield a correct answers. how should i do this?