Pressure under the water

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Problem# h2phy1 - Pressure converted inside the Aorta

Problem# h2phy2 - Pressure inside vein

Problem# h2phy3 - Pressure on the floor

Problem# h2phy4 - Pressure under the sea

An enterprising diver reasons that if a typical 20 cm.
long snorkel tube works, a 6.0 m. long tube should
also. If he foolishly uses such a tube, what is the pressure
different Δp between the external pressure
on him and the air pressure in his lungs? Why is he in danger?

Strategy - the rule "Must have" of Mr.Zhang ®

Absolute pressure (P) The difference between absolute pressure and atmospheric pressure is called gauge pressure. P =  (Pg) + (Po) Absolute pressure - Atmospheric pressure = Gauge pressure       Material or Object         Density (kg/m3)     Water: 20 οC and 1 atm 0.998x103 Sea water: 20 οC and 1 atm 1.024x103   1 atm = 760 mmHg = 760 torr = 29.9 in.Hg =101.325 kPa = 14.7 lb/in.2

Solution The diver at depth L = 6.0 m without the snorkel tube. The external pressure on him is given by ; P =  Po + ρgh ΔP=P-Po=ρgL ; because L=h     =(1000 kg/m3)(9.8 m/s2)(6.0m)     =5.9x104 Pa ∴The pressure difference is about 0.6 atm, is sufficient to collapse the lungs and force the still pressurized blood into them,a process known lung squeeze. "thoracic squeeze, also called Lung Squeeze, compression of the lungs and thoracic (chest) cavity that occurs during a breath-holding dive under water. During the descent, an increase in pressure causes air spaces and gas pockets within the body to compress." credited : Britannica

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