2-1
Solutions Manual
for
Fundamentals of Thermal Fluid Sciences
5th Edition
Yunus A. Çengel, John M. Cimbala, Robert H. Turner
McGraw-Hill, 2017
Chapter 2
BASIC CONCEPTS OF THERMODYNAMICS
PROPRIETARY AND CONFIDENTIAL
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2-4
2-13 The variation of density of atmospheric air with elevation is given in tabular form. A relation for the variation of
density with elevation is to be obtained, the density at 7 km elevation is to be calculated, and the mass of the atmosphere
using the correlation is to be estimated.
2-6
2-21E The temperature of ambient air given in C unit is to be converted to F, K and R units.
R 419.67
67.45940
T
2-22E A temperature change is given in F. It is to be expressed in C, K, and R.
Pressure, Manometer, and Barometer
2-23C The atmospheric pressure, which is the external pressure exerted on the skin, decreases with increasing elevation.
Therefore, the pressure is lower at higher elevations. As a result, the difference between the blood pressure in the veins and
the air pressure outside increases. This pressure imbalance may cause some thin-walled veins such as the ones in the nose to
burst, causing bleeding. The shortness of breath is caused by the lower air density at higher elevations, and thus lower
amount of oxygen per unit volume.
2-24C The blood vessels are more restricted when the arm is parallel to the body than when the arm is perpendicular to the
2-25C No, the absolute pressure in a liquid of constant density does not double when the depth is doubled. It is the gage
pressure that doubles when the depth is doubled.
2-26C Pascal’s principle states that the pressure applied to a confined fluid increases the pressure throughout by the same
2-27C The density of air at sea level is higher than the density of air on top of a high mountain. Therefore, the volume flow
2-7
2-28 The pressure in a vacuum chamber is measured by a vacuum gage. The absolute pressure in the chamber is to be
2-29 The pressure in a tank is given. The tank’s pressure in various units are to be determined.
kN 1
kPa 1
2-30E The pressure in a tank in SI unit is given. The tank’s pressure in various English units are to be determined.
lbf/in 1
in 144
kPa 1
2-31E The pressure given in mm Hg unit is to be converted to psia.
Hg mm 1
2-8
2-32E The pressure in a tank is measured with a manometer by measuring the differential height of the manometer fluid.
The absolute pressure in the tank is to be determined for the cases of the manometer arm with the higher and lower fluid
level being attached to the tank .
2-33 The pressure in a pressurized water tank is measured by a multi-fluid manometer. The gage pressure of air in the tank
is to be determined.
2-11
2-39 The mass of a woman is given. The minimum imprint area per shoe needed to enable her to walk on the snow without
sinking is to be determined.
2-40E The vacuum pressure given in kPa unit is to be converted to various units.
2-12
2-41 A mountain hiker records the barometric reading before and after a hiking trip. The vertical distance climbed is to be
determined.
2-42 A barometer is used to measure the height of a building by recording reading at the bottom and at the top of the
building. The height of the building is to be determined.
2-16
2-48 Problem 2-47 is reconsidered. The effect of the manometer fluid density in the range of 800 to 13,000 kg/m3 on
the differential fluid height of the manometer is to be investigated. Differential fluid height against the density is to be
plotted, and the results are to be discussed.
7578
8933
10289
11644
13000
1076
913.1
792.8
700.5
627.5
02000 4000 6000 8000 10000 12000 14000
0
2200
4400
[kg/m^3]
hmm [mm]
2-17
2-49 The air pressure in a tank is measured by an oil manometer. For a given oil-level difference between the two columns,
the absolute pressure in the tank is to be determined.
2-50 The air pressure in a duct is measured by a mercury manometer. For a given
mercury-level difference between the two columns, the absolute pressure in the
2-51 The air pressure in a duct is measured by a mercury manometer. For a given
mercury-level difference between the two columns, the absolute pressure in the duct is
to be determined.
2-19
2-53E The pressure in a natural gas pipeline is measured by a double U-tube manometer with one of the arms open to the
atmosphere. The absolute pressure in the pipeline is to be determined.