Answer
121.5 N
Work Step by Step
F= $ k\frac{|q_{1}q_{2}|}{r^{2}}$
Thus, we find:
$ k\frac{|q_{1}q_{2}|}{r^{2}}$= 1.5 N
When the distance is reduced to one-ninth of its original value,
F= $ k\frac{|q_{1}q_{2}|}{(\frac{r}{9})^{2}}$= $ k\frac{|q_{1}q_{2}|}{r^{2}} \times 9^{2}$ =$ 1.5 N\times81$ = 121.5 N
