Look at photo C. The temperature of the air
in the room is -5 °C. The
temperature of the drinks is
70°C.
Will energy flow from the
drinks to the room or from
the room to the drinks?
Explain your answer.

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.