An electron and a positron that are initially moving very slowly collide with one another and release a gamma ray in the process. The gamma ray is ejected at an angle of 60° with respect to the...

An electron and a positron that are initially moving very slowly collide with one another and release a gamma ray in the process. The gamma ray is ejected at an angle of 60° with respect to the positive x-axis (see Figure 2.30). What is the energy of the gamma ray, what is its frequency of vibration, and what is its momentum in the positive x direction?