本题目来源于试卷: 美国2021年物理杯赛真题 PHYSICS BOWL 2021，类别为 美国物理杯赛(Physics Bowl)
[单选题]
An ice skater is rotating with her arms extended. When she pulls in her arms, her rate of rotation increases. No external torques act on the skater. Which of the following statements is true?
A. Her moment of inertia increased.
B. Her kinetic energy is conserved.
C. Her angular momentum decreased.
D. She does work when pulling in her arms.
E. Her angular momentum increased.
参考答案: D
本题详细解析:
$W= F∆x$
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