Torque: Torque is the rotational force that causes an object to rotate about a fixed axis or pivot point. It is the product of the force applied and the perpendicular distance between the line of action of the force and the axis of rotation.
Angular Momentum: Angular momentum is the measure of an object's rotational motion, taking into account both the object's mass and its distance from the axis of rotation. It is a conserved quantity in a closed system.
Closed System: A closed system is a system that does not exchange matter with its surroundings, but may exchange energy. In the context of angular momentum, a closed system is one where the total angular momentum remains constant unless acted upon by external torques.