What is anti proton?

A proton and an anti-proton annihilate, producing two photons. Find the energy, frequency, and wavelength of each photon emitted if the initial kinetic energies of the proton and anti-proton are negligible.

When given a velocity in a proton/ anti-proton question, why is the given velocity not used when solving for the energy (E) or for the momentum (p)?

In proton-antiproton annihilation , a proton and anti-protoncollide and disappear, producing electromagnetic radiation.
If each particle has a mass of 1.67* 10^-27 kg and they are at restjust before they annihilate each other ,find the total energy ofthe radiation produced .give the answer in both joules and eV,please