thermodynamics

CONTENT SUBSECTION PROB NO. Concept Problems 1-18 Properties and Units 19-22 Force and Energy 23-34 Specific Volume 35-40 Pressure 41-56 Manometers and Barometers 57-77 Temperature 78-83 Review problems 84-89 Borgnakke and Sonntag Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which this textbook has been adopted. Any other reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful. In-Text Concept Questions Borgnakke and Sonntag Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which this textbook has been adopted. Any other reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful. Q . W 2.a Make a control volume around the turbine in the steam power plant in Fig. 1.1 and list the flows of mass and energy that are there. Solution: We see hot high pressure steam flowing in at state 1 from the steam drum through a flow control (not shown). The steam leaves at a lower pressure to the condenser (heat W exchanger) at state 2. A rotating shaft gives a rate of energy (power) to the electric generator set. 2.b Take a control volume around your kitchen refrigerator and indicate where the components shown in Figure 1.6 are located and show all flows of energy transfer. Solution: The valve and the cold line, the evaporator, is inside close to the inside wall and usually a small blower distributes cold air from the freezer box to the refrigerator room. . Q leak The black grille in the back or at the bottom is the condenser that gives heat to the room air. The compressor sits at the bottom. cb T Borgnakke and Sonntag Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which this textbook has been adopted. Any other reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful. 2.c Why do people float high in the water when swimming in the Dead Sea as compared with swimming in a fresh water lake? As the dead sea is very salty its density is higher than fresh water density. The buoyancy effect gives a force up that equals the weight of the displaced water. Since density is higher the displaced volume is smaller for the same force. Borgnakke and Sonntag Excerpts from this work may be reproduced by instructors for distribution on a not-for-profit basis for testing or instructional purposes only to students enrolled in courses for which this textbook has been adopted. Any other reproduction or translation of this work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful. 2.d Density of liquid water is  = 1008 – T/2 [kg/m3 ] with T in oC. If the temperature increases, what happens to the density and specific volume? Solution: The density is seen to decrease as the temperature increases.  = – T/2 Since the specific volume is the inverse of the density v = 1/ it will increase. 2.e A car tire gauge indicates 195 kPa; what is the air pressure inside? The pressure you read on the gauge is a gauge pressure, P, so the absolute pressure is found as ` P = Po + P = 101 + 195 = 296 kPa