Description

This applet illustrates the principle of conservation of momentum and the relationship between angular momentum, moment of inertia, and angular velocity.

Angular momentum equals the moment of inertia times the angular velocity. When a skater brings her arms in, she decreases her moment of inertia, which causes her angular velocity to increase in proportion because the product of her moment of inertia and her angular velocity remains a constant as long as there are no forces acting on the skater.

Purpose

The principle of conservation of momentum inherently involves motion. Static textbook drawings often do not intuitively convey concepts of motion well. An interactive applet provides both motion as well as interaction to allow the student to experiment with the simulation and to try to predict the outcome, thereby learning by doing.