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Question
What is the efficiency of a subject on a treadmill who puts out work at the rate of 100 W while consuming oxygen at the rate of 2.00 L/min? (Hint: See Table 7.5.)
Question by OpenStax is licensed under CC BY 4.0.
Final Answer
14.3%
Solution Video

OpenStax College Physics Solution, Chapter 7, Problem 50 (Problems & Exercises) (0:44)

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Video Transcript

This is College Physics Answers with Shaun Dychko. This person running on a treadmill has a work output rate of 100 watts and the rate of energy use is 2 liters of oxygen per minute and in this table [7.5], we can look up the row that has an oxygen consumption of 2.00 liters per minute and read across to this column and see how that many watts that is so this person is using 700 watts. So the efficiency is the useful work output divided by the energy consumed to do that work. So that's 100 watts divided by 700 watts which is 14.3% efficiency.