Final answer:
The efficiency of a person on a treadmill who puts out work at 100 W while consuming oxygen at a rate of 2.00 L/min is approximately 23.9%.
Step-by-step explanation:
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 can be calculated using the formula:
Efficiency = Useful Power Output / Total Energy Input
In this case, the useful power output is 100 W and the total energy input can be calculated by multiplying the rate of oxygen consumption (2.00 L/min) by the energy content of oxygen (5.0 kcal/L).
So, the total energy input would be 2.00 L/min x 5.0 kcal/L = 10 kcal/min. Converting 10 kcal/min to watts using the conversion factor 1 kcal = 4.1868 kJ and 1 J/s = 1 W, we get:
Total Energy Input = 10 kcal/min x 4.1868 kJ/kcal x 1 J/s / 1000 J = 41.868 W.
Therefore, the efficiency is:
Efficiency = 100 W / 41.868 W = 0.239 or 23.9% (rounded to one decimal place).