Newton's third law of motion states that for every action, there is an equal and opposite reaction. It describes how forces act in pairs between interacting objects - the force exerted by object A on object B is equal in strength to the force exerted by object B on object A, but in the opposite direction. Action and reaction force pairs do not cancel each other out because they act on different objects rather than the same object. Examples given include jumping, where a person pushes down on the ground and the ground pushes up with an equal force, and a rocket, where the exhaust gas pushes down on the engine and the engine pushes up with an equal thrust.