A figure skater spins with arms extended. When she pulls her arms in, what happens to her angular momentum?
Practice Questions
1 question
Q1
A figure skater spins with arms extended. When she pulls her arms in, what happens to her angular momentum?
Increases
Decreases
Remains the same
Becomes zero
Angular momentum remains the same; however, her angular velocity increases due to a decrease in moment of inertia.
Questions & Step-by-step Solutions
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Q
Q: A figure skater spins with arms extended. When she pulls her arms in, what happens to her angular momentum?
Solution: Angular momentum remains the same; however, her angular velocity increases due to a decrease in moment of inertia.
Steps: 7
Step 1: Understand what angular momentum is. It is a measure of how much motion an object has while rotating.
Step 2: Know that angular momentum is conserved in a closed system, meaning it stays the same unless acted on by an external force.
Step 3: Recognize that the figure skater has a certain amount of angular momentum when her arms are extended.
Step 4: When the skater pulls her arms in, she changes her shape, which affects her moment of inertia (how mass is distributed around the axis of rotation).
Step 5: Moment of inertia decreases when she pulls her arms in because her mass is closer to the center of rotation.
Step 6: Since angular momentum is conserved, if the moment of inertia decreases, her angular velocity (the speed of her spin) must increase to keep the angular momentum the same.
Step 7: Conclude that her angular momentum remains constant, but her spinning speed increases when she pulls her arms in.
