Ablock of mass m is attached to ideal spring of constant k. when the spring is neither stretched nor compressed, block is at the equilibrium position (x = 0).
assume the force between the mass and the spring obeys hooke’s law: fs = - kx, where x is the displacement and fs is the restoring force. the restoring force is always directed toward the equilibrium position. in this example of vibrational motion, the restoring force illustrates newton's

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?