Conservation of Angular Momentum Video Lessons

Concept

# Problem: A figure skater on ice spins on one foot so there is minimal friction. She pulls in her arms and her rotational speed increases. Choose the best statement below: 1.When she pulls in her arms, her rotational kinetic energy is conserved and therefore stays the same. 2. When she pulls in her arms, the work she performs on them turns into increased rotational kinetic energy. 3. When she pulls in her arms, her angular momentum decreases so as to conserve energy. 4.When she pulls in her arms, her rotational kinetic energy must decrease because of the decrease in her moment of inertia. 5. When she pulls in her arms, her moment of inertia is conserved. 6. When she pulls in her arms, her rotational potential energy increases as her arms approach the center.

###### Problem Details

A figure skater on ice spins on one foot so there is minimal friction. She pulls in her arms and her rotational speed increases. Choose the best statement below:

1.When she pulls in her arms, her rotational kinetic energy is conserved and therefore stays the same.

2. When she pulls in her arms, the work she performs on them turns into increased rotational kinetic energy.

3. When she pulls in her arms, her angular momentum decreases so as to conserve energy.

4.When she pulls in her arms, her rotational kinetic energy must decrease because of the decrease in her moment of inertia.

5. When she pulls in her arms, her moment of inertia is conserved.

6. When she pulls in her arms, her rotational potential energy increases as her arms approach the center.