3. Conservation of Relativistic Momentum and Energy An electron with a kinetic energy of K maka a headon collision with a positron at rest; [A positron is an antimatter particle with the same mam as the electron but with opposite charge.) In the collision the two particles annihilate each other to produoe two Gamma rays of equal energy, each travelling at equal angles, 3, relative to the electron's direction of motion. {Gamma rays [1} are massless particles of electromagnetic radiation having energy E. = P75) {3.) [2 marks) Derive an expression for the initial momentum ofthe electron, p, in terms of K and other known quantities of the electron. [b] [1 mark] Write an expression for the energy of each Gamma ray, E1: then use this to write an expression for the momentum of each 'T-ray. [c] [1 mark) Write an exprion for the angle 9. [d] [1 marks) Calculate the values of ET and 9 for K=3_DDD MeV