A physics student is standing on an initially motionless,frictionless turntable with rotational inertia 0.31kg·m2. He's holding a wheel of rotational inertia0.22 kg·m2 spining at 125 rpm about a vertical axis, as we showed in Fig.11.8. When he turns the wheel upside down, student and turntablebegin rotating at 79 rpm.
a) What is the student's mass, considering him to be acylinder 30 cm in diameter?
b) How much work did he do in turning the wheel upside down? Neglect the distance between the axes of the turntable and wheel.