Question

A ballet dancer spins about a vertical anus at 16 rpm with arms outstretched with the arms folded moment of inertia about the same anis q rotation changes to 75% calculate the new speed of rotational

Answer 1

64/3 rpm

Answer 2

Conservation of angular momentum: $I_1 \omega_1 = I_2 \omega_2$. Given $\omega_1 = 16$ rpm and $I_2 = 0.75 I_1$. Substitute: $I_1 (16) = (0.75 I_1) \omega_2$. Solve for $\omega_2$: $\omega_2 = \frac{16}{0.75} = \frac{64}{3}$ rpm.