This model is generally applicable, but mathematically very complicated. In introductory mechanics it will only be used to describe the motion of a gyroscope.

Only used in problems involving a gyroscope.

Technically, any number of rigid bodies. In practice, only used in analyzing gyroscopes (single rigid body with a fixed pivot point).

Only external torques need be considered. Internal torques do not change the system's angular momentum.

• A delta-L diagram analogous to the of .