Aball is thrown straight up into the air. at each of the following instants, is the magnitude of the ball's acceleration greater than g, equal to g, less than g, or zero? air resistance may be neglected.
a) just after leaving your hand?
b) at the very top (maximum height)?
c) just before hitting the ground?

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?