Answer
$v=6.63\times 10^6\frac{m}{s}$
Work Step by Step
In equilibrium state,
$\frac{1}{2}mv^2=qV$
This can be written as,
$v=\sqrt\frac{2qV}{m}$
We plug in the known values to obtain:
$v=\sqrt\frac{2(1.6\times 10^{-19})(125)}{9.109\times 10^{-31}}$
$v=6.63\times 10^6\frac{m}{s}$
