## College Physics (4th Edition)

The work done by the applied force is $8.45~J$
We can find the electric potential energy: $U = \frac{k~q_1~q_2}{r}$ $U = \frac{(9.0\times 10^9~N~m^2/C^2)(6.5\times 10^{-6}~C)(6.5\times 10^{-6}~C)}{0.045~m}$ $U = 8.45~J$ When the charges are very far apart, we can assume that the electric potential energy is zero. Therefore, the work done by the applied force is $8.45~J$.