Question
A 55.0 -kg woman cheats on her diet and eats a 540 Calorie $(540 \mathrm{kcal})$ jelly doughnut for breakfast. (a) How many joules of energy are the equivalent of one jelly doughnut? (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 $15.0 \mathrm{cm} .$ (c) If the human body is only $25.0 \%$ efficient in converting chemical potential energy to mechanical energy, how many steps must the woman climb to work off her breakfast?
Step 1
- We know that 1 kilocalorie (kcal) is equivalent to 4184 joules (J). - Therefore, the energy content of the jelly doughnut in joules is: \[ 540 \, \text{kcal} \times 4184 \, \text{J/kcal} = 2,259,360 \, \text{J} \] Show more…
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A 55.0-kg woman cheats on her diet and eats a 540 Calorie (540 kcal) jelly doughnut for breakfast. (a) How many joules of energy are the equivalent of one jelly doughnut? (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 15.0 cm. (c) If the human body is only 25.0% efficient in converting chemical potential energy to mechanical energy, how many steps must the woman climb to work off her breakfast?
A 55.0 -kg woman cheats on her dietand eatsa 540 -Calorie $(540 \mathrm{kcal})$ jelly doughnut for breakfast. (a) How many joules of energy are the equivalent of one jelly doughnut? (b) How many steps must the woman climb on a very tall stairway to change the gravitational potential energy of the womanEarth system by a value equivalent to the food energy in one jelly doughnut? Assume the height of a single stair is $15.0 \mathrm{cm}$ (c) If the human body is only $25.0 \%$ efficient in converting chemical potential energy to mechanical energy, how many steps must the woman climb to work off her breakfast?
A $55.0-\mathrm{kg}$ woman eats a 540 Calorie $(540 \mathrm{kcal})$ jelly doughnut for breakfast. (a) How many joules of energy are the equivalent of one jelly doughnut? (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 $15.0 \mathrm{~cm} .$ (c) If the human body is only $25.0 \%$ efficient in converting chemical potential energy to mechanical energy, how many steps must the woman climb to work off her breakfast?
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