A59-kg woman eats a 583 calorie (583 kcal) jelly doughnut for breakfast. (a) how many joules of energy are the equivalent of one jelly doughnut? j (b) how many steps must the woman climb on a very tall stairway to change the gravitational potential energy of the woman-earth system by a value 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 29% efficient in converting chemical potential energy to mechanical energy, how many steps must the woman climb to work off her breakfast? stairs