The food calorie, equal to 4186 J, is a measure of how much energy is released w

Question

The food calorie, equal to 4186 J, is a measure of how much energy is released when food is metabolized by the body. A certain brand of fruit-and-cereal bar contains 130 food calories per bar.

If a 62.0 kg hiker eats one of these bars, how high a mountain must he climb to "work off" the calories, assuming that all the food energy goes only into increasing gravitational potential energy?

h=

If, as is typical, only 25.0 % of the food calories go into mechanical energy, what would be the answer to part (a)? (Note: In this and all other problems, we are assuming that 100 % of the food calories that are eaten are absorbed and used by the body. This is actually not true. A person's "metabolic efficiency" is the percentage of calories eaten that are actually used; the rest are eliminated by the body. Metabolic efficiency varies considerably from person to person.)

h=

Explanation / Answer

a)

Here Work Done is Change in gravitatioal potential energy

mgh =130*4186

62*9.81*h =130*4186

h=894.71 m

b)

=>mgh =0.25*130*4186 =136045

62*9.81*h =136045

h=223.68 m

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