How do dolphins communicate with each other

An apple is falling from a tree. disregarding air resistance, which diagram shows the free-body diagram of the force or forces acting on the apple?

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?

If a stone with an original velocity of 0 is falling from a ledgeand takes 8 seconds to hoybthe ground whays the final velocity of the stone