ETYM Latin See Moment.
1. An impelling force or strength; SYN. impulse.
2. The product of a body's mass and its velocity.
In physics, the product of the mass of a body and its linear velocity. The angular momentum of an orbiting or rotating body is the product of its moment of inertia and its angular velocity. The momentum of a body does not change unless it is acted on by an external force; angular momentum does not change unless it is acted upon by a turning force, or torque.
The law of conservation of momentum is one of the fundamental concepts of classical physics. It states that the total momentum of all bodies in a closed system is constant and unaffected by processes occurring within the system. Angular momentum is similarly conserved in a closed system.