Question

In 1953 Sir Edmund Hillary and Tenzing Norgay made the first successful ascent of Mt. Everest. Part A How many slices of bread did each climber have to eat to compensate for the increase of the gravitational potential energy of the system climbers-Earth? (One piece of bread releases about 1.0×106J of energy in the body.) Assume that the height of Mt. Everest is 8850 m, the weight of a person is about 75 kg , and efficiency in converting the body's chemical energy into mechanical work is 11.0 %.

Answer 1

60

Step-by-step explanation:

We start calculating the total work required to climb up the Everest.

The total energy would be,

`W=mgh`

Where m is the mass of the person (75kG)

g is the gravitational force (9.8m/s^2)

h is the high (8850m)

`W= (75)(9.8)(8850) = 6.5*10^6J`

From our problem we have that only 11% of chemical energy (
`\alpha`)is converted to mechanical energy(
`\Gamma`),

`11\%\alpha = \Gamma`

For this situation,

`\Gamma=W`

`11\%\alpha = W`

`\alpha = (W)/(11\%)`

`\alpha = \frac{6.5*10^6} {11\%}`

`\alpha = 59.1*10^(6)`

We know that only 1 piece of bread release
`1.0*10^6J`, then

`\eta * (1*10^6) = 59.1*10^(6)`

`\eta = (59.1*10^6)/(1*10^6)`

`\eta = 59.1`

Therefore it is necessary 60 breads