According to Newton's law of reciprocal action, what happens to momentum in a closed system?

In a closed system, the law of conservation of momentum states that the total momentum remains constant unless acted upon by an external force. This principle aligns with Newton's third law, which asserts that for every action, there is an equal and opposite reaction. As a result, when two objects interact within a closed system—such as in collisions or other interactions—their momenta will transfer between them, but the overall momentum of the system will not change.

This concept can be illustrated through various scenarios, like elastic and inelastic collisions. In elastic collisions, both momentum and kinetic energy are conserved, while in inelastic collisions, momentum is still conserved, but kinetic energy is not. Regardless of the specific type of interaction, as long as no external forces are acting on the system, the total momentum will remain constant.

Thus, the assertion that momentum is always conserved in a closed system correctly reflects the principles outlined in Newton’s laws of motion.