We'll point you toward old answers: .
For starters, though, mv2/2= p2/2m (where p is momentum) isnt even close to the right expression for energy for a particle that's moving fast in your reference frame. It just works for v << c. For particles traveling at c, the correct expression is pc. The full expression for the energy, working for all speeds, is sqrt(p2c2+mc4), where m is the rest mass.
Mike W.
(published on 04/26/2015)