Answer:
potential energy=ε Qq/r. Putting values of charge along with sign and calculating the potential energy will tell whether the resultant force is attractive or repulsive.
Explanation:
potential energy=ε Qq/r
q and Q are charges on each particle
So in case the particles have attractive force between them, one particle will be negative and the other will be positiive. The result will be negative.
In case the particles have repulsive forces, the charge on both particles will be either positive or negative. The result will be positive