Bicyclists in the Tour de France do enormous amounts of work during a race. For

Question

Bicyclists in the Tour de France do enormous amounts of work during a race. For example, the average power per kilogram generated by Lance Armstrong (m = 75.0 kg) is 6.50 W per kilogram of his body mass. (a) How much work does he do during a 115-km race in which his average speed is 11.7 m/s? (b) Often, the work done is expressed in nutritional Calories rather than in joules. Express the work done in part (a) in terms of nutritional Calories, noting that 1 joule = 2.389 x 10-4 nutritional Calories.

(a) Number______ Units_____

(b) Number______ Units______

Explanation / Answer

First: Calculate the total power Lance's body is capable of
P=6.5*75=487.5 W

Second: Calculate the time it takes to finish the race
t=115000/11.7=9829.05 s

Third: Using the equation Power=Work/time...Calculate
Work=P*t=9829.05*487.5=4791661.875 J

If 1 joule = 2.389 x 10-4 then 1144.728 cal

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