Answer:
E = V q energy attained by charge q thru potential energy V
E = 1/2 m v^2 kinetic energy of charge q
1/2 m v^2 = V q equating energy attained
v^2 = 2 V q / m
v = (2 V q / m)^1/2
The final speed is proportional to the square roots of V, q, and inverse of square root of m.
