## Essential University Physics: Volume 1 (3rd Edition)

(a) We know that $U=-\int Fdx$ $U=-\int (\frac{A}{x^2})dx$ $U=\frac{A}{x}$ Thus, the potential energy difference is: $\Delta U=\frac{A}{x_2}-\frac{A}{x_1}$ (b) The potential energy difference is given as $\Delta U=\frac{A}{\infty}-\frac{A}{x_1}=-\frac{A}{x_1}$