I don't understand what attraction means. Is it the force between electron and proton? In wires, only free electrons in conduction band can flows and their velocity is far less than relativistic regime as far as I know. But the only information propagation is close to the speed of light.
I'm reading some accelerator physics paper showing the momentum unit for the accelerated particles as MeV/c.
I'm not interested in the momentum but energy thus I really want to convert this to energy.
How it is done? Simply multiplying c? if so, there must be some reason for justify...