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question 18
a figure skater is spinning with her arms held straight out. the rotational speed of her fingertips is
slightly greater than that of her elbows
less than that of her elbows
equal to that of her elbows
far exceeds that of the elbows

Explanation:

When a figure skater spins with arms out, all parts of her arm (fingertips, elbows) rotate about the same axis. Rotational speed (angular velocity, $\omega$) is the same for all points on a rigid body rotating about a fixed axis. Linear speed ($v = r\omega$) differs by radius, but rotational speed (angular velocity) is equal for co - rotating points on the same rigid body. So the rotational speed of fingertips and elbows is equal.

Answer:

C. equal to that of her elbows