Question

The time rate of the total angular momentum of a system of particles about a point (taken as the origin of our frame of reference) is equal to the sum of the external torques (i.e. the torques due to external forces) acting on the system taken about the same point. If τext = dL/dt Hence, if τext = 0, dL/dt = 0 Thus, if the total external torque on a system of particles is zero, then the total angular momentum of the system is conserved, i.e. it remains constant.

If a body is rotating about an axis passing through its center of mass, the angular momentum of the body is directed along its