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 189-km race in which his average speed is 12.5 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.

Answer 1

Answer:

E=1760.93 cal

Explanation:

a) First we find the total time

t=x/v

t=189000/12.5

t=15120 seconds

Now we multiply the time by his total wattage

E=t*W

E=(15120)(6.5)(75)=7371000 joules

As,

1 joule = 2.389 x 10-4

So, in term of nutritional Calories

E=7371000 * 2.389*$10^{-4}$

E=1760.93 Cal