Bicyclists in the Tour de France do enormous amounts of work during a race. For
ID: 3897420 • Letter: B
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 139-km race in which his average speed is 11.9 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.
Explanation / Answer
a)
time taken = distance/speed = 139000/11.9 = 11680.6 seconds
Power per kg = 6.5 W
Power for mass of 75 kg = 75*6.5 = 487.5 W
Work done = Power*time = 487.5 *11680.6 = 5,694,293 J = 5.694 MJ
b)
in calories, work done = 5,694,293*2.389*10^-4 = 1,360.3665 calories = 1.36 kcal
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.