Question

The mass of a star is 1.770×1031 kg and it performs one rotation in 21.90 days. Find its new period (in days) if the diameter suddenly shrinks to 0.590 times its present size. Assume a uniform mass distribution before and after.

A figure skater is spinning with an initial angular speed of 9.8rad/s. He then pulls his arms in, reducing his moment of inertia to 0.27 times its original value. What is his angular speed after pulling in his arms?

Three children are riding on the edge of a merry–go–round that is 88 kg, has a 1.80–m radius, and is spinning at 22.0 rpm. The children have masses of 24.0, 30.0, and 35.0 kg. If the child who has a mass of 30.0 kg moves to the center of the merry–go–round, what is the new angular velocity in rpm? (You do not need to enter any units.)

Answer 1