A hot iron ball of mass 200 g is cooled to a temperature of 22°C from 100°C. How much heat was lost in the process?
(Ciron = 0.444 J/g°C)
Q =mcAT

Aperson stands on a platform, initially at rest, that can rotate freely without friction. the moment of inertia of the person plus the platform is ip. the person holds a spinning bicycle wheel with its axis horizontal. the wheel has moment of inertia iw and angular velocity ωw. take the ωw direction counterclockwise when viewed from above. part a what will be the angular velocity ωp of the platform if the person moves the axis of the wheel so that it points vertically upward?