As explained by Hyperphysics, angular momentum is calculated by finding the product of the moment of inertia and the angular velocity of a rotating body or system. The moment of inertia with respect to an axis is the product of the mass times the distance from the axis squared, and angular velocity is the rate of change of angular displacement.
Einstein Online defines angular momentum, for an object orbiting a central point, as the product of the object’s mass times its distance from the axis times the velocity at which it orbits around the center. Angular momentum is understood as the momentum of rotation, or an object’s resistance to change in rotation. Angular momentum is a vector quantity requiring both magnitude and direction. The direction of the angular momentum vector is the same as the axis of rotation of the object using the right-hand rule, explains Real World Physics.
Encyclopædia Britannica states that the total angular momentum for a given object or system isolated from external forces is a constant, which is known as the law of conservation of angular momentum. The units for angular momentum are kilogram meters squared per second (kg ? m2 / sec). A child’s yo-yo builds angular momentum as the string unwinds and the spool spins, causing the yo-yo to continue spinning after reaching the end of the string, states HowStuffWorks.