If the distance between the spheres is halved,how will this affect the magnitude of the force?

Question

And also this other question here:what does the fact that the force is repulsive tell you about the charges?...PLEASE HELP,MY TEACHER WILL PUNISH ME IF I DON'T DO TSHIS HOMEWORK.

Answer 1

k Q1 Q2 / d^2

d2 = .5 d1

so d2^2 = .25 d1^2

1/.25 = 4 times

like charges repel and for heavens sake READ THE BOOK !!!!