If object A exerts a force on object B, object B must reply with a force of equal size and in the opposite direction, according to Newton’s third law of motion.

This law illustrates nature's symmetry: forces always exist in pairs, and one body cannot exert a force on another without also being subjected to one. This law is sometimes referred to as action-reaction, with the action being the force exerted and the reaction being the force received as a result.