Question

two egatively charged particles repel one other with an electrostatic force of 5 newtons. determine how the sign and manitude of this force changes when; a. the distance between them is doubled, b. the distance is cut in half., c. one particle's charge is doubled., d both particles charges are tripled.

Answer 1

I will be happy to critique your thinking.

Answer 2

Use Coulomb’s Law
F= k•q1•q2/r^2
The for the first question:
F1 = k•q1•q2/(2r)^2
Find the ratio
F1/F = (k•q1•q2)• r^2/(k•q1•q2)• (2r)^2 =1/4.
F1 =F/4=5/4=1.25 N .
….
Act like that for other cases.