Problem 1.54 (Schroeder’s Intro to Thermal Physics)

Problem 1.54

A 60-kg hiker wishes to climb to the summit of Mt. Ogden, an ascent of 5000 vertical feet (1500 m).

(a) Assuming that she is 25% efficient at converting chemical energy from food into mechanical work, and that essentially all the mechanical work is used to climb vertically, roughly how many bowls of corn flakes (standard serving size 1 ounce, 100 kilocalories) should the hiker eat before setting out?
(b) As the hiker climbs the mountain, three-quarters of the energy from the corn flakes is converted to thermal energy. If there were no way to dissipate this energy, by how many degrees would her body temperature increase?

(c) In fact, the extra energy does not warm the hiker’s body significantly; instead, it goes (mostly) into evaporating water from her skin. How many liters of water should she drink during the hike to replace the lost fluids? (At , a reasonable temperature to assume, the specific latent heat of vaporization of water is 580 cal/g, 8% more than at .)

Solution:

Problem 1.54

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