1.If a 64.0 kg hiker eats one of these bars, how high a mountain must he climb t

Question

1.If a 64.0 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?
2.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.)

Explanation / Answer

a) Energy released by eating a bar=150*4186= 627900J

let the height climbed be h

Then, 64*9.8*h=627900

h=1001 m

b) Since only, 25% goes into mechanical energy,

64*9.8*h=627900*0.25=250.28 m

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