Answer:
if the old force is F, the new force is F/9
Explanation:
Recall that the Coulomb force between to charges is inversely proportional to the square of the distance between the charges.
Therefore, if the original distance "d" changes now to be "3d" (tripled), the denominator of the force expression will change from:
thus reducing the original force by a factor 1/9
So if the old force is F, the new force is F/9
