A 65-kg woman cheats on her diet and eats a 612-Calorie (612 kcal) jelly doughnut for breakfast.
(a) How many joules of energy are the equivalent of one jelly doughnut?
_______ J
(b) How many stairs must the woman climb to perform an amount of mechanical work equivalent to the food energy in one jelly doughnut? Assume the height of a single stair is 15 cm.
_____ stairs
(c) If the human body is only 21% efficient in converting chemical energy to mechanical energy, how many stairs must the woman climb to work off her breakfast?
______ stairs