The angular momentum of a rigid object is the product of the moment of inertia of the object and its angular velocity. The total angular momentum of a system is always constant. Moment of Inertia(I) is the body's tendency to resist angular acceleration. Find here the angular momentum formula to calculate the angular momentum and the moment of inertia of an object. For finding I, as per the Moment of Inertia Formula dividing the product of mass and squared radius value by 2 gives the I.