## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)

$F=1.44 \times 10^{-3} N$
By the Work-Energy Theorem; P.E. = Work done $U=F.D$ $F=\frac{U}{D}=\frac{72 \times 10^{-6}}{5 \times 10^{-2}}=1.44 \times 10^{-3} N$ Hence, $F=1.44 \times 10^{-3} N$.