Angular momentum is defined as?

Angular momentum is a key concept in physics that describes the momentum of an object in rotational motion. It is specifically defined as the product of an object's rotational inertia (often referred to as the moment of inertia) and its angular velocity. The moment of inertia represents how mass is distributed relative to the axis of rotation, while angular velocity is a measure of how quickly the object is rotating around that axis.

When an object spins or rotates, the angular momentum helps determine how that object will behave under the influence of external forces or torques. Because it depends on both the object's mass distribution (rotational inertia) and how fast it is rotating, angular momentum is conserved in an isolated system, meaning it remains constant unless acted upon by an outside force.

The other options describe different physical concepts, such as linear motion, linear momentum, or the dynamics of circular motion, but they do not capture the essence of angular momentum, which is intrinsically linked to rotational motion and not simply linear speed or mass.