The positive mutual potential energy of a system containing two charges corresponds to
Potential energy:
The potential energy of charges is the energy that is due to the Coulomb force and varies with the distance between them. The potential energy of a system of 2 charges is
are the charges.
is the distance between the charges .
is a constant whose value is .
Therefore if the potential energy of a system of 2 charges is positive, it means that the charges are of the same nature and repel each other.