Question

A spinning skater whose arms are at her sides then stretches out her arms horizontally:

a) She continues to spin at the same rate
b) She spins more rapidly
c) She spins more slowly

Answer 1

When a spinning skater stretches out her arms horizontally, she spins more slowly due to the conservation of angular momentum.

Step-by-step explanation:

When a spinning skater stretches out her arms horizontally, she spins more slowly.

This is because of the conservation of angular momentum. Angular momentum is the product of moment of inertia and angular velocity. When the skater stretches out her arms, her moment of inertia increases because her mass is spread out over a larger distance from the axis of rotation. To conserve angular momentum, her angular velocity decreases, resulting in a slower spin.

For example, think about how a figure skater spins with her arms tucked in compared to when her arms are extended. With her arms tucked in, her moment of inertia decreases, so she spins faster. When she extends her arms, her moment of inertia increases, causing her to spin more slowly.