Answer:

Explanation:
Using Newton's second law, we calculate the magnitude of the electric force between the spheres:

The magnitude of the charge in both spheres is the same. So, we calculate the charge, using Coulomb's law:

Metamorphism occurs because some minerals are stable only under certain conditions of pressure and temperature. When pressure and temperature change, chemical reactions occur to cause the minerals in the rock to change to an assemblage that is stable at the new pressure and temperature conditions.