In all of the following problems, use the following constants:
In all problems ignore gravity unless it is explicitly mentioned.
I. Both balls have a positive charge.
II. Both balls have a negative charge.
III. One ball has a positive charge, and the other, a negative charge.
IV. One ball is charged and the other is neutral.
In a certain experiment, two balls made of cork are hung from insulating strings. There is a force to the effect of pulling the balls together, due to charges on the balls. What can be concluded?