An electron has a total energy equal to five times its rest energy(0.511MeV).
--What is its momentum (in MeV/c)?
E(total) = [mass(electron)*c^2]/[sq. root of (1- velocity^2/c^2)]
----I converted 2.555MeV (total energy) to 4.088e-13 J and plugged that in for E(total) to solve for velocity
The Attempt at a Solution
I used the EQN above to solve for velocity of the electron [in terms of c(speed of light)].
I then divided the total energy (2.555MeV) by this velocity (which I got to be 0.979680884c) and got the answer 2.61MeV/c. When I submit it, it says I'm within 10%, but I didn't round any numbers until the can't see what I did wrong...