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question 19
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a figure skater is spinning with her arms held straight out. the tangential speed of her fingertips is
greater than that of her elbows
slightly less than that of her elbows
much less than that of her elbows
equal to that of her elbows

Explanation:

When a figure skater spins, all parts of her body (elbows, fingertips) rotate with the same angular velocity ($\omega$). Tangential speed $v$ is given by $v = r\omega$, where $r$ is the distance from the axis of rotation. Fingertips are farther from the axis than elbows, so $r_{fingertips} > r_{elbows}$. Since $\omega$ is constant, $v_{fingertips} = r_{fingertips}\omega$ and $v_{elbows} = r_{elbows}\omega$. Thus, $v_{fingertips} > v_{elbows}$.

Answer:

A. greater than that of her elbows