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.
a. estimate the amount of work in breathing done by each person in the course of 24 h.
b. 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). how much mass (in kg) could one lift to 100 m in height with this amount of work? since 1000 kg is about 1 ton, your answer should give you some sense for how much your body is working even when you are “resting.”
need with a and b