What term describes the quantity of angular motion in a body?

The quantity of angular motion in a body is referred to as angular momentum. This term encompasses both the mass of the object and its velocity as it moves around a specific point or axis, taking into account the distance from that point or axis to the line of action of the object's motion. Angular momentum is a vector quantity, which means it has both a direction and magnitude.

In essence, angular momentum reflects how difficult it would be to stop the object from rotating, and it remains conserved in an isolated system where there are no external torques acting on it. This principle is crucial in various applications, from sports to engineering, as it helps in understanding the behavior of rotating bodies.

The other options represent different concepts related to motion but do not define the quantity of angular motion itself. Angular velocity measures the rate of change of an angle over time, centripetal force describes the force required to keep an object moving in a circular path, and torque relates to the rotational force that causes an object to rotate around an axis. Each of these has its own important role in understanding dynamics but they do not directly define angular motion.