What potential difference is needed to accelerate a He + ion (charge +e, mass 4 u) from rest to a speed of 2.0 * 10^6 m/s?
Kf + Uf = Ki + Ui
U = qV where V is potential difference (volts)
K = (1/2)mv^2
The Attempt at a Solution
I chose the rest point to be r = 0, so even with U = Kq_1q_2/r, it would equal zero at the start.
(1/2)mv^2 = -qV
V = (-1/2q)mv^2
m = u* 1.66*10^-27 kg/u = 1.66*10^-27 kg
V = -(2/(1.6*10^-19 Coulombs)) * (1.66*10^-27 kg)(2.0*10^6 m/s)^2
= -83000 volts
Is this right?