A student ( m=85 kg) runs up the stairs (h= 2.8 m) in 1.42 seconds.
a) Calculate the Energy change of the student.
b) Calculate the efficiency of the student if it took 9339 J of chemical potential energy for the student to run up the stairs
c) Calculate the output power of the student in horsepower ( 1 h.p=746 W)
d) in the lab you walked up a flight of stairs to determine your own power. describe two reasons why the efficiency of the climb was not 100%
- NCSLv 71 month agoFavorite Answer
a) ΔE = mgΔh = 85kg*9.8m/s²*2.8m = 2332 J
b) ε = 100% * 2332/9339 = 25%
c) P = 2332J / 1.42s = 1642 W
d) The efficiency can never be 100%. You burn energy even without climbing stairs.