Suppose you have two small pith balls that are 5.5 cm apart and have equal charges of -29 nc?

The question is missing, however, I guess the problem is asking for the value of the force acting between the two balls.

The Coulomb force between the two balls is:

where  is the Coulomb's constant,  is the intensity of the two charges, and  is the distance between them.

Substituting these numbers into the equation, we get


The force is repulsive, because the charges have same sign and so they repel each other.