A proton (mass mmm, charge eee) and an alpha particle (mass 4m, charge 2e2e2e) are accelerated from rest through the same electric potential difference V V\,V in a vacuum. If the final speed of the proton is vvv, what is the final speed of the alpha particle?
v2\frac{v}{2}2v
v2\frac{v}{\sqrt{2}}2v
2v\sqrt{2}v2v
2v2v2v
