My Notes Ask Your Teacher 10. -1 points OSColPhys2016 14.2.WA.008. Sara, who wei

Question

My Notes Ask Your Teacher 10. -1 points OSColPhys2016 14.2.WA.008. Sara, who weighs 66 kg, is on a guilt trip after eating a 638-Calorie (638 kcal) breakfast of pancakes loaded with fruits, cream, and syrup. She decides to work out before going to her weekly weight-watchers' meeting. If the height of a single stair is 12 cm, and her body is only 27% efficient in converting chemical energy to mechanical energy, determine the number of stairs Sara must climb to cancel out the Calories consumed. stairs Additional Materials Reading

Explanation / Answer

Use Conservation of energy,

Change in potential energy from climbing the stairs = Calories consumed x efficiency

638 kcal = 2669392 J

so, mgH = 0.27 x 2669392

=> H = 1114.31 m

and height of one stair is 12 cm = 0.12 m

therefore, the number of stairs needed to climb in order to fully burn the calories consumed will be:

n = H/h = 1114.31/0.12 = 9285.9 or approximately 9286 stairs.

Related Questions

Navigate

• Browse (All)
• Browse M
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.