Thermodynamics 1 (MEP 261)
Midterm ( 30 Marks)
Model Answer
Class ZA, Date: April 18, 2012
Name: University ID:
1- The water in a tank is pressurized by air, and the pressure is measured by a multifluid
manometer as shown in Fig. 1. Determine the gage pressure of air in the tank if
( 5 Marks)
Fig. 1
h1 = 0.1m, h2 = 0.15m, h1 = 0.23m. Take the densities of water, oil and mercury to be 1000
kg/m3, 850 kg/m3 and 13,600 kg/m3, respectively.
, Solution
p1 +ρwaterg h1+ ρoilg h2 = patm +ρmercuryg h3
p1gage = (9.81 m/s2)[(13600 kg/m3)(0.23m)- (1000 kg/m3)(0.1m)- (850
kg/m3)(0.15m)]{1N/1kgms-2}{1kPa/1000Nm-2}
Hence, p1gage = 28.45 kPa
Midterm ( 30 Marks)
Model Answer
Class ZA, Date: April 18, 2012
Name: University ID:
1- The water in a tank is pressurized by air, and the pressure is measured by a multifluid
manometer as shown in Fig. 1. Determine the gage pressure of air in the tank if
( 5 Marks)
Fig. 1
h1 = 0.1m, h2 = 0.15m, h1 = 0.23m. Take the densities of water, oil and mercury to be 1000
kg/m3, 850 kg/m3 and 13,600 kg/m3, respectively.
, Solution
p1 +ρwaterg h1+ ρoilg h2 = patm +ρmercuryg h3
p1gage = (9.81 m/s2)[(13600 kg/m3)(0.23m)- (1000 kg/m3)(0.1m)- (850
kg/m3)(0.15m)]{1N/1kgms-2}{1kPa/1000Nm-2}
Hence, p1gage = 28.45 kPa
