Final answer:
The angular momentum of an object is conserved when there is no net external torque acting on it.
Step-by-step explanation:
The conservation of angular momentum states that the angular momentum of an object remains constant if there is no net external torque acting on it. This means that if the net torque is zero, the angular momentum will remain unchanged. In other words, the initial angular momentum is equal to the final angular momentum in the absence of external torque.
For example, consider a spinning figure skater. When the skater's arms are extended, the moment of inertia is greater, resulting in a lower angular speed. However, when the skater brings their arms in, the moment of inertia decreases and the angular speed increases while keeping the angular momentum constant.