Keeping Your Cool A 65kg cyclist is pedaling down the road at 12km/h , using a t

Question

Keeping Your Cool A 65kg cyclist is pedaling down the road at 12km/h , using a total metabolic power of 480W . A certain fraction of this energy is used to move the bicycle forward, but the balance ends up as thermal energy in his body, which he must get rid of to keep cool. On a very warm day, conduction, convection, and radiation transfer little energy, and so he does this by perspiring, with the evaporation of water taking away the excess thermal energy.


To keep from overheating, the cyclist must get rid of the excess thermal energy generated in his body. If he cycles at this rate for 2 hours, how many liters of water must he perspire, to the nearest 0.1 liter?

Explanation / Answer

Power converted to body heat=0.75*480W=360W

energy converted to body heat over 2 hours=360*3600*2=2.592*106J

This should be used to evaporate water.

Let m kg be evaporated.

m*2270000=2.592*106

m=1.1kg=1.1l

Related Questions

Navigate

• Browse (All)
• Browse K
• Subjects

---

---

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