Errors Applying Newton's Third Law

Newton's Third Law implies that if any object applies a force on a second object, then the second object will always simultaneously apply an equal, opposite and collinear force of the same type on the first object.

Imagine a stationary box on the ground experiencing a downward gravitational force and an equal and opposite upward normal force. These two forces cannot be a Newton's Third Law pair because each force of a Newton's Third Law pair must operate on different objects.

Imagine two stationary charged balls where the gravitational and electrostatic forces are of equal strength. Each charged ball exerts a gravitational force on the other ball that is equal, opposite and collinear to the electrostatic force it experiences from the other ball. Nevertheless, a gravitational force and an electrostatic force cannot be a Newton's Third Law pair because both forces are not of the same type.