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5. (20 pts) (Manometer) A manometer is used to measure the air pressure in a tank The fluid used has a specific gravity of 1.25, and the differential height between the two arms of the manometer is 28 in. If the local atmospheric pressure is 12.7 psía, determine the absolute pressure in the tank for the cases of the manometer arm with the a) higher and (b) lower fluid level being attached to the tank. P Air 28 in SG= 1.25 Patm = 12.7 psia

User Jaythaking
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Final answer:

The absolute pressure in the tank is 1403.606 psia when the higher fluid level is attached and -1378.206 psia when the lower fluid level is attached.

Step-by-step explanation:

A manometer is a device used to measure pressure. In this case, we have a U-tube manometer with one side open to the atmosphere. The height difference between the two arms of the manometer is 28 in. We are given that the specific gravity of the fluid used in the manometer is 1.25 and the local atmospheric pressure is 12.7 psia.

To determine the absolute pressure in the tank, we need to consider two cases:

(a) Higher fluid level attached to the tank:

We can calculate the absolute pressure in the tank by adding the gauge pressure to the atmospheric pressure:
Absolute pressure = Atmospheric pressure + Gauge pressure

The gauge pressure is given by:
Gauge pressure = Differential height x Specific gravity x Density of fluid x Acceleration due to gravity

Substituting the given values:
Gauge pressure = 28 in x 1.25 x 12.7 psia x 32.17 ft/s^2 / 1 in = 1390.906 psia

Therefore, the absolute pressure in the tank when the higher fluid level is attached is:
Absolute pressure = 12.7 psia + 1390.906 psia = 1403.606 psia

(b) Lower fluid level attached to the tank:

Using the same formula as above, the gauge pressure when the lower fluid level is attached is:
Gauge pressure = -28 in x 1.25 x 12.7 psia x 32.17 ft/s^2 / 1 in = -1390.906 psia

Therefore, the absolute pressure in the tank when the lower fluid level is attached is:
Absolute pressure = 12.7 psia - 1390.906 psia = -1378.206 psia

User James Pack
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