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LEARN MORE REMARKS The welght of the atmosphere results in Po at the surface of

ID: 2039565 • Letter: L

Question

LEARN MORE REMARKS The welght of the atmosphere results in Po at the surface of the oll layer. Then the weight of the oill and the weight of the water combine to create the pressure at the bottom. QUESTION Why does air pressure decrease with increasing altitude? (Select all that apply.) O Hot air rises. C The weight of the air above is smaller There is more air below to push up more strongly Colder air is less dense. The weight of the air below is smaller. D Less air above pushes down. Consider what causes pressure in a fluld and how it is related to the fluid above and below the point of Interest. Does air contract or expand if cooled, and how does that affect its density? PRACTICE IT Use the worked example above to help you solve this problem. In a huge oil tanker, salt water has flooded an oil tank to a depth of h2-4.95 m. On top of the water is a layer of oil h1 = 8.25 m deep, as in the cross-sectional view of the tank as shown in the figure. The oil has a density of 0.700 g/cm3. Find the pressure at the bottom of the tank. (Take 1,025 kg/m2 as the density of salt water.) Pa EXERCISE HINTS: GETTING STARTED I PM STUCKI Calculate the pressure on the top lid of a chest buried under 3.95 meters of mud with density 1.75 x 103 kg/m3 at the bottom of a 12.5-m-deep lake. 252.122 X Follow the example, but not too closely. For instance, water is in the middle layer of the exercise but at the bottom layer of the example. Pa Need Help? Read It

Explanation / Answer

1) The pressure of the air decreases with increasing altitude because:

a) The weight above the ai above is smaller

b) Less air above pushes down

2)

The pressure at the bottom will be = Patm + Poil + Pwater

Patm = 101325 Pascal

Poil = density * g* height of the oil column = 700 * 9.81* 8.25 = 56652.75 Pascal

Pwater = density * g* height of the water column = 1025*9.81*4.95 = 49773.4875 Pascal

Therefore, Pressure at the bottom = 207751.2375 Pascal

And if we ignore atmospheric pressure, P = 106426.2375 Pascal

3)

Pressure = density * g* height of the mud column = 1750*9.81*12.5 = 214593.75 Pascal (without atmospheric pressure)

With atmospheric pressure, P+101325 = 315918.75 Pascal