please help:

Question

A repelling force occurs between two charged objects when the charges are of
a. unlike signs
b. like signs
c. equal magnitude
d. unequal magnitude

Answer 1

Look up Coulomb's Law and take your best guess. If you don't know the answer to this, you have not been studying the subject at all.

Answer 2

Even if you can't remember the value of the Coulomb's Law constant (like me), try to remember these two important facts:
(1) like charges repel; opoosite charges attract
(2) The force between two charges is inversely proportional to the square of the distance, and is the same on both charges