Angular Momentum

Angular momentum is related to linear momentum in that it measures the amount of motion in a body. Linear momentum measures the amount of linear motion, while angular momentum measures the amount of angular motion.

The equation for linear motion is mass times velocity, while for angular momentum it is moment of inertia times angular velocity (makes you wonder if mass = inertia?). Since nothing is ever at rest because there is no absolute zero-motion reference frame (as far as we know), everything has momentum, both linear and angular.