Acrane lifts a large cement slab weighing 2,200 n to a height of 15 m. what is the pe of the slab? remember, weight is measured in newtons (n), and is equal to mass times gravity.

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?