What is the Average Depth of the ocean?

Answer asap! the weather patterns on earth are shown in this image. explain why there are convection currents; why there are hotter and colder parts of earth.

When a book falls from a shelf to the ground without anyone pushing on it, no work is done on the book. true or false

Abird flies directly overhead from where you stand at an altitude of 300.0 m and at a speed horizontal to the ground of 20.0 m/s. the bird has a mass of 2.0 kg. the radius vector to the bird makes an angle \thetaθ with respect to the ground. the radius vector to the bird and its momentum vector lie in the xyxy-plane. what is the bird’s angular momentum about the point where you are standing?