The winning time for the 2005 annual race up 86 floors of the Empire State Build
ID: 2261247 • Letter: T
Question
The winning time for the 2005 annual race up 86 floors of the Empire State Building was 10min and 49s . The winner's mass was 60kg .(a)If the efficiency in climbing stairs is 25
% , what total energy did the winner expend during the race.Etot=?KJ
(b)How many food Calories did the winner "burn" during the race?Q=? cal
(c)Of those Calories, how many were converted to thermal energy? E thermal=?cal
l (d) What was the winner's metabolic power in watts during the race up the stairs?P=?W
thermal=?cal
Explanation / Answer
A) change efficiency to a decimal (25% = 0.25)
187 kJ/0.25 = 748 kJ
B) one calorie = 4.2 kJ so...
748 kJ/4.2 kJ/cal = 178 cal
c) since he was only 25% efficient, the remaining energy went straight to heat...
178 x 0.75 = 134 cal
D) 10 m 49 s = 649 s
I assume the metabolic power is based on total energy output so...
Power = Energy/Time = 748 000 J/649 s = 1150 W
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