Scuba divers experience increasing pressure as they descend in water due to the

Question

Scuba divers experience increasing pressure as they descend in water due to the extra weight of the water above them. There is an increase in pressure of 1.0 atm for every 33 ft descended. This must be added to the atmospheric pressure of 1.0 atm at the surface because this pressure doesn't go away under water. If we approximate that a human lung expands by 0.50 L per breath, compute the PV work of a lung at:

The earth's surface (in J):

A depth of 165 ft (in J):

*****The correct answer is not 0.28!!

Explanation / Answer

a) At the earth's Surface

PV work= Pressure(constant) * dV (dV= change in volume)

At earth's Surface, P=1atm = 101325Pa

Given dV(change in volume of lungs)= 0.5L = 0.0005 m3 ( as 1m3=1000L)

Therefore, work done(per breath)= 101325*.0005 J (1Pa*1m3 = 1J)

=50.66J

a) At depth of 165ft

PV work= Pressure(constant) * dV (dV= change in volume)

At earth's Surface, P=1atm = 101325Pa

At 165ft below, P=1atm+(165/33)atm = 6atm= 6*101325Pa

Given dV(change in volume of lungs)= 0.5L = 0.0005 m3 ( as 1m3=1000L)

Therefore, work done(per breath)= 6*101325*.0005 J (1Pa*1m3 = 1J)

=303.97J

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