A) a particle of rest mass m is travelling so that its total energy is 2me2. it collides with a stationary particle of rest mass m to form a new single particle. what is the rest mass of the new particle? 9 marks b) a photon hits an electron at rest and produces an electron-positron pair according to the reaction γ + e-→ e-t-e-+ et, what is the smallest possible photon energy for this to occur? you may assume that electrons and positrons have equal masses. 8 marks c) a photon rocket uses pure radiation as the propellant. if the initial and final rest masses of the rocket are m, and m, show that the final speed v of the rocket, as measured in its initial rest frame, sat isfies m, 8 marks hint: if the total momentum of all photons emitted from the rocket has magnitude p then the total energy of all those photons is ecial to