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Introductory Physics Homework Help
How Many Food Calories with Efficiency %
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[QUOTE="Edemardil, post: 6031767, member: 648658"] I figured out (a) but I am having trouble with (b): (a) What is the efficiency of an out of condition professor who 2.10e5 J of useful work while metabolizing 500 kcal of food energy? (b) How many food calories would a well-conditioned athlete metabolize in doing the same work with an efficiency of 25%?[h2]Homework Equations[/h2] OE + Wnc = OEf η = Work_out / Work_in Work_in = η * work_out [h2]The Attempt at a Solution[/h2] For (a) I converted the calories to Joules 1 kcal = 4184 J 500 kcal (4184J/1 kcal) = 2.1e6 J η = W_out/W_in η = (2.10e5J) / (2.10e6J) η = 10% (b) I assume I could input the 25% into the equation and work backwards but it's not giving me a correct anwser. I've tried the following: 0.25 = (2.10e5J) / (kcal) kcal = (0.25)(2.10e5J) kcal = 52500J Convert the Joules to kcal and get something like 12kcal But that's wrong also. [/QUOTE]
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How Many Food Calories with Efficiency %
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