1. The problem statement, all variables and given/known data An electron with a kinetic energy of 1MeV collides with a stationary positron. The two particles annihilate each other and produce 2 photons, of equal energy traveling at angle theta to the direction of the electron. Find, a. The momenta of the electron b.the energy of the photons c.the momentum of the photons d. the angle theta of the photons rest mass electron/positron = 0.511MeV/c^2 speed of light c = 3x10^8 m/s E^2=(Eo+Ek)^2=p^2*c^2+(mc^2)^2 3. The attempt at a solution ok for a. which is all i have done so far im pretty sure all i have to do is solve for p p=root((((Eo+Ek)^2)-((mc^2)^2))/c)=??? i am getting very confused with the units in this question .. I am getting 1.422MeV/c please can any tell me if this is right?