Which statement best describes the energy changes that occur while a child is riding on a sled down a steep, snow-covered hill? a
Kinetic energy decreases and potential energy increases.
b
Both potential energy and kinetic energy decrease.
c
Both potential energy and kinetic energy increase.
d
Kinetic energy increases and potential energy decreases.

Assume that a person skiing high in the mountains at an altitude of h = 15100 ft takes in the same volume of air with each breath as she does while walking at sea level. determine the ratio of the mass of oxygen inhaled for each breath at this high altitude compared to that at sea level. assume that the air composition (i.e. % of air that is oxygen) is the same at sea level as it is at 15100 ft.