The angular momentum of a body is its rotational velocity, at any given point in time, multiplied by its moment of inertia.

Moment of inertia (I) is the measure of a body’s resistance to changes in rotation or tumbling motion about an axis from its position. Moment of inertia depends on the distribution of mass about that axis.

It can be thought as how much effort would be needed to change it or stop it from rotating if external forces are not applied to it either way; so for example a spinning top has greater moment compared with an ice skater doing a spin because both have the same linear speed but one’s distance depends on using up kinetic energy and slowing down from friction while the other one stays in the same radius and doesn’t lose speed.

I = (r * m * g) / (2 * r)

where,

r is radius of curvy body;

m is mass; and

g is gravity.