I recently started studying Special Relativity for fun through reading the classic book Spacetime Physics. I came across a practice problem that I have difficult understanding:
An electron moving with some kinetic energy K collides with another electron to produce 2 gamma rays travelling at different angles with respect to the moving electron. Determine an expression for the energies as a function of the electron mass, energy, and angle of outgoing rays.
I'm not quite sure how to set up the conservation momentum equations to solve for this...?