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 136-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 10-4nutritional Calories.

Explanation / Answer

a)

here

P = 6.5 * 75 = 487.5 W

he covers 136 km with a speed of 11.9 m/s

so the time is t = distance / speed

t = 136000 / 11.9 = 11428.57 sec = 3.1746 hr

then

P = W / t

W = P * t

W = 487.5 * 11428.57 = 5.57 * 10^6 J

b)

in calories

W = 5.57 * 10^6 * 2.389 * 10^-4 = 1330.67 cal

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.