Video Summary: This learning video describes within an action orientation certain often difficult-to-understand concepts of Newtonian physics. The conservation of momentum is extended to rotational situations, and some of the results may be counter-intuitive! As Professor Lewin states in the opening segment, the prerequisite necessary for this lesson includes familiarity with the concepts of torque, angular velocity, angular momentum and moment of inertia. This interactive video lesson can easily be completed within a 55-minute class period, and the only material required is a blackboard/whiteboard to write on. During the breaks between video segments, students will be asked to think about and discuss: conditions under which angular momentum is either conserved or not conserved; examples in which the moment of inertia changes; a human ice skater and a rough estimation of her moment of inertia; as well as other topics.