Human beings expend energy during expansion and contraction of their lungs in br

Question

Human beings expend energy during expansion and contraction of their lungs in breathing. Each exhalation from the lungs of an adult involves pushing out about 0.5 liter of gas against 1.0 atm. pressure. This occurs about 15,000 times in a 24-h day. Estimate the amount of work in breathing done by each person in the course of 24 h. To get a feeling for how much work this represents, imagine using it to raise a mass to the top of a 30-story building (about 100 m). First make a guess at how large a weight could be raised by this amount of work: 1 kg (2.2 lb), 10 kg, 100 kg, 1000 kg (about 1 ton). Now do the calculation and draw some conclusions about how much your body is working even when you are "resting."

Explanation / Answer

PLEASE RATE:)

a)

work done=P x V x 15000=1 x 0.5 x 15000 lit atm=7500 x 101.4 J=760.4 KJ

b)

Let this work is equal to lifting a mass m to 100m then
m*9.8*100=760500
OR m=776 Kg
from this we can say that even when the body is resting it performs a work that is equivalent to lifting a 776 Kg mass to a height of 100m

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