In a hot day’s race, a bicyclist consumes 8L water over 4 hrs.(adsbygoogle = window.adsbygoogle || []).push({});

Assume that 80% of his energy goes into evaporating this water as sweat. (This isn't a bad approximation, b/c the mechanical efficiency of a bicycle rider is only ~20%, w/ the rest of the energy consumed going into heat.)

How much total energy, in kcal, did the rider use during the race?

I know that 8L is evaporated by heat (body). I can obtain the mass of water, giving me Q.

I need to use the equation Lxm= Q, from this get 80% of total --> total

Latent heat and vaporization

You can get the mass from knowing 1L= 1000cm^3

Because there are 8L, you have 8000cm^3

Convert to grams knowing the density of water: 1g/cm^3

(8000cm^3)(1g/cm^3)= 8000g or 8 kg water.

I am stuck from here please help!

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# Homework Help: Sweaty Biker and Energy Consumption

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