Electron/proton kinetic electric energy

[bocobuff]

Homework Statement

an electron starting from rest acquires 3.53keV of kinetic energy in moving from A to B. how much kinetic energy would a proton acquire moving from B to A.

Homework Equations

1/2mv²
m_e=9.11e-31 kg
m_p=1.67e-29 kg
1eV=1.6e-19 J

The Attempt at a Solution

conservation of energy, using potential energy = 0 at ending points and KE=3.53 at ending point so it should be equal to initial potential energy. But that's equal to q*E*s and i don't know E or s

 

[bocobuff]

nvm, it should just be the same as the electron due to conservation of energy
so =3.63 keV