A figure skater spinning on ice pulls her arms inward, reducing her moment of inertia from I1 to I2 (I2 < I1). Her angular velocity changes from omega1 to omega2 such that:
Choose the correct answer
omega2 = omega1
omega2 = I1 x omega1 / I2 (angular momentum conserved: I1 omega1 = I2 omega2, so omega2 > omega1)
omega2 = I2 x omega1 / I1 (slower)
omega2 depends on height only
Correct Answer
B. omega2 = I1 x omega1 / I2 (angular momentum conserved: I1 omega1 = I2 omega2, so omega2 > omega1)
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Conservation of angular momentum: H = I x omega = constant (when no external torque). If I decreases (arms in), omega increases proportionally. I1 omega1 = I2 omega2. This principle applies to collisions, diving, gymnastics, satellite attitude control. External torque (friction at ice) is neglected for short durations.
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