Conservation of relativistic momentum and energy, pion decays 1. The problem statement, all variables and given/known data A small particle (pion), traveling at a velocity V, decays into two rays, γ1 and γ2. Find the Momentum and Energy of γ1 and γ2 if: a) γ1 is in line with V, and b) if γ1 is perpendicular to V. I drew out the problem and listed all of the givens: http://imageshack.us/a/img832/648/physprob.png [Broken] 2. Relevant equations Eπ=Eγ1+Eγ2 Pπ=Pγ1+Pγ2 E=P*c (for rays, no mass) E=mc^2/sqrt(1-V^2/c^2) (for particle) E=K+E0 P=mV/sqrt(1-V^2/c^2) (for particle) E0=mc^2 3. The attempt at a solution Below is my attempt at a solution so far: http://img593.imageshack.us/img593/5444/solutionattempt.png [Broken] So far, I found: m∏=2.406E-28 kg V=2.827E8 m/s Ebefore=405 MeV Pbefore=382.1 MeV/c I know that the total momentum after the particle decays has to equal the momentum before and same with the energy. I am just unsure how to finish the problem at this point. Can I assume that Pγ1=Pγ2 after the disintegration? I am also confused on how to handle part b) where γ1 is perpendicular to V. Thanks in advance!