In a closed, isolated system of particles, forces internal tothe system do not change the motion of the system as a whole. Thevelocity of the center of mass of such a system is unchanged unlessthe system is impacted by some net external force. In this context,and with the aid of a single illustration, explain what is meant bya) internal force, and b) external force. c) Explain why internalforces have no effect on the system’s motion.
