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Homework Help: Determine absolute pressure

  1. Apr 18, 2017 #1
    1. The problem statement, all variables and given/known data
    A manometer is used to measure the pressure of a gas in a tank. The fluid used has a the specific gravity of 0.85, and the manometer column height is 55 cm, as shown in figure 3-20. If the local atmospheric pressure is 96 kPa, determine the absolute pressure within the tank.

    2. Relevant equations
    P = SG x p

    P = P atm + pgh

    3. The attempt at a solution

    The reading of manometer attached to a tank is to be determined.

    Assumptions The density of a gas in the tanks is much lower than the density of the manometer fluid.

    Properties The specific gravity of the manometer fluids is given to be 0.85. We take the standard density of water to be 1000kg/m³.

    Analysis The density of the fluid is obtained by multiplying its specific gravity by the density of water,

    P = SG ( p H2O ) = (0.85)(1000kg/m³) = 850 kg/m³

    P = P atm + pgh

    = 96 kPa + (850kg/m³)(9.81m/s²)(0.55m) x (1N/1kg.m/s^2)(1kPa/1000N/m^2)

    = 100.6 kPa

    *edit I figured it out
  2. jcsd
  3. Apr 20, 2017 #2


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    Looks correct, to me.
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