need to understand it asap!!

What quantity do units represent in value

Ihave this 50 question test the layer of earth's atmosphere where atoms and molecules escape into space is referred to as the a) exosphere b) ionosphere. c) mesosphere d) thermosphere

Consider a small frictionless puck perched at the top of a fixed sphere of radius r. if the puck is given a tiny nudge so that it begins to slide down, through what vertical height will it descend before it leaves the surface of the sphere? [hint: use conservation of energy to find the puck's speed as a func e conservation of energy to find the puck's speed as a function of its height at what value of this normal force does the puck leave the sphere? ] here on the puck.