Imagine that you have a sample of an unknown element and that you know only the elements mass number without directly measuring the number of protons in the nucleus of the element what other information would you need to know to identify the element?

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?