$**$ A student sits motionless on a stool that can turn friction$-$free about its vertical axis $($total rotational inertia $/).$ The student is handed a spinning bicycle wheel, with rotational inertia $I_{\text{w}\text{h}\text{e}\text{e}\text{l}\text{,}},$ that is spinning about a vertical axis with a counterclockwise rotational velocity ${}_0.$ The student then turns the bicycle wheel over $($that is$,$ through $180).$ Estimate, in terms of ${}_0,$ the final rotational velocity acquired by the student.