Answer to Question #269098 in Classical Mechanics for joseph

Question

1. A manometer containing oil (p = 850 kg/m³) is attached to a tank filled with air. If the oil-level difference between the two columns is I50 cm and the atmospheric pressure is 98 kPa, determine the absolute pressure of the air in the tank.

2. Pressure is often given in terms of a liquid column and is expressed as “pressure head." Express the standard atmospheric pressure in terms of (a) mercury (SG = 13.6). (b) water (SG = 1.0). and (c) glycerin (SG = 1.26) columns. Explain why we usually use mercury in manometers.

Answer 1

1.

$P=P_0+\rho gh=110.5~kPa,$

2.

$P\sim \rho,$

a)

$1~\text{atm}=760$ mm of mercury,

b)

$1~\text{atm}=10336$ mm of water,

c)

$1~\text{atm}=8203$ mm of glycerin.