Wolfram Demonstrations Project

13,000+ Open Interactive Demonstrations
Powered by Notebook Technology »

Spinning Ice Skater

Initializing live version
Download to Desktop

Requires a Wolfram Notebook System

Interact on desktop, mobile and cloud with the free Wolfram Player or other Wolfram Language products.

A spinning ice skater is a common example of conservation of angular momentum. When the skater starts spinning with hands outstretched, the angular velocity is low, but the spinning becomes very fast as the hands are pulled in. What happens is that as the moment of inertia decreases, the angular velocity increases, so that the angular momentum is conserved.

Contributed by: Enrique Zeleny (March 2011)
Open content licensed under CC BY-NC-SA

Snapshots

Details

The moment of inertia provides a measure of the difficulty of changing the rotational motion of a body.

The conservation of angular momentum establishes that

where and are the initial and final moments of inertia and and are the corresponding angular velocities.

The skater's arms are treated as a dumbbell, approximated as the moment of inertia of a mass at the end of a rod:

,

where r is the distance from the axis of rotation to the center of mass of the ends of the dumbbell; then

.

See P. J. Nolan, Fundamentals of College Physics, 2nd ed., Dubuque, IA: Wm. C. Brown, 1995.

Embed Code

Take advantage of the Wolfram Notebook Emebedder for the recommended user experience.

Related Demonstrations More by Author
Browse all topics
Feedback (field required)
Email (field required) Name
Occupation Organization
Note: Your message & contact information may be shared with the author of any specific Demonstration for which you give feedback.
Send