A 59-kg woman cheats on her diet and eats a 457-Calorie (457 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 27% efficient in converting chemical energy to mechanical energy, how many stairs must the woman climb to work off her breakfast? =________stairs