(a) To determine The temperature at the interface of the two layers. Explanation At steady state, the rates of energy conduction are equal through each layer. Express the rate of energy conduction through insulation layer. Q ˙ A = − κ i [ T 2 − T 1 L i ] (I) Here, surface area is A , thermal conductivity is κ , initial temperature is T 1 , temperature at the interface of the two layers is T 2 , and thickness is L i . Express the rate of energy conduction through siding layer. Q ˙ A = − κ s [ T 3 − T 2 L s ] (II) Here, final temperature is T 2 . Equate Equations (I) and (II) to obtain the temperature at the interface of the two layers − κ i [ T 2 − T 1 L i ] = − κ s [ T 3 − T 2 L s ] T 2 = κ i L i T 1 + κ s L s T 3 ( κ i / L i ) + ( κ s / L s ) (III) Conclusion: Substitute 0 .058 Btu / h ⋅ ft ⋅ ° R for κ s , 0 .75 in . for L s , 0 .029 Btu / h ⋅ ft ⋅ ° R for κ i , 3 in . for L i , 67°F for T 1 and − 8 °F for T 3 in Equation (III). T 2 = [ ( 0 .029 Btu / h ⋅ ft ⋅ ° R ) ( 3 in . ) × 12 in . ft ] ( 67°F ) + { [ ( 0 .058 Btu / h ⋅ ft ⋅ ° R ) ( 0 (b) To determine The rate of heat transfer through the wall of surface area.

Appendices to accompany Fundamentals of Engineering Thermodynamics, 8e

8th Edition

ISBN: 9781118957219

Author: Michael J. Moran, Howard N. Shapiro

Publisher: WILEY

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Chapter 2.7, Problem 50P

(a)

To determine

The temperature at the interface of the two layers.

(b)

To determine

The rate of heat transfer through the wall of surface area.

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Chapter 2.7, Problem 49P

Chapter 2.7, Problem 51P

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Chapter 2 Solutions

Appendices to accompany Fundamentals of Engineering Thermodynamics, 8e

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Ch. 2.7 - Prob. 11E Ch. 2.7 - Prob. 12E Ch. 2.7 - 13. What form does the energy balance take for an...Ch. 2.7 - 14. What forms of energy and energy transfer are...Ch. 2.7 - Prob. 15E Ch. 2.7 - 16. Steve has a pedometer that reads kilocalories...Ch. 2.7 - Prob. 17E Ch. 2.7 - Prob. 1CU Ch. 2.7 - Prob. 11CU Ch. 2.7 - Prob. 12CU Ch. 2.7 - Prob. 13CU Ch. 2.7 - Prob. 14CU Ch. 2.7 - 15. In mechanics, the work of a resultant force...Ch. 2.7 - 16. What direction is the net energy transfer by...Ch. 2.7 - 17. The differential of work, δW, is said to be an...Ch. 2.7 - Prob. 18CU Ch. 2.7 - Prob. 19CU Ch. 2.7 - Prob. 20CU Ch. 2.7 - Prob. 21CU Ch. 2.7 - Prob. 22CU Ch. 2.7 - Prob. 23CU Ch. 2.7 - Prob. 24CU Ch. 2.7 - Prob. 25CU Ch. 2.7 - 26. State the sign convention used in...Ch. 2.7 - Prob. 27CU Ch. 2.7 - Prob. 28CU Ch. 2.7 - Prob. 29CU Ch. 2.7 - 30. Based on the mechanisms of heat transfer, list...Ch. 2.7 - Prob. 31CU Ch. 2.7 - Prob. 32CU Ch. 2.7 - 33. The total energy of a closed system can change...Ch. 2.7 - 34. The energy of an isolated system can only...Ch. 2.7 - 35. If a closed system undergoes a thermodynamic...Ch. 2.7 - Prob. 36CU Ch. 2.7 - Prob. 37CU Ch. 2.7 - Prob. 38CU Ch. 2.7 - Prob. 39CU Ch. 2.7 - Prob. 40CU Ch. 2.7 - Prob. 41CU Ch. 2.7 - 42. A process that is adiabatic cannot involve...Ch. 2.7 - Prob. 43CU Ch. 2.7 - Prob. 44CU Ch. 2.7 - Prob. 45CU Ch. 2.7 - Prob. 46CU Ch. 2.7 - 47. A rotating flywheel stores energy in the form...Ch. 2.7 - Prob. 48CU Ch. 2.7 - Prob. 49CU Ch. 2.7 - 50. If a closed system undergoes a process for...Ch. 2.7 - Prob. 51CU Ch. 2.7 - Prob. 52CU Ch. 2.7 - Prob. 53CU Ch. 2.7 - Prob. 54CU Ch. 2.7 - 2.1 A baseball has a mass of 0.3 lb. What is the...Ch. 2.7 - 2.2 Determine the gravitational potential energy,...Ch. 2.7 - 2.3 An object whose weight is 100 lbf experiences...Ch. 2.7 - 2.4 A construction crane weighing 12.000 lbf fell...Ch. 2.7 - 2.5 An automobile weighing 2500 lbf increases its...Ch. 2.7 - 2.6 An object of mass 1000 kg, initially having a...Ch. 2.7 - 2.7 A 30-seat turboprop airliner whose mass is...Ch. 2.7 - 2.8 An automobile having a mass of 900 kg...Ch. 2.7 - 2.9 Vehicle crumple zones are designed to absorb...Ch. 2.7 - 2.10 An object whose mass is 300 lb experiences...Ch. 2.7 - Prob. 11P Ch. 2.7 - 2.12 Using KE = Iω2/2 from Problem 2.11a, how fast...Ch. 2.7 - 2.13 Two objects having different masses are...Ch. 2.7 - 2.14 An object whose mass is 100 lb falls freely...Ch. 2.7 - 2.15 During the packaging process, a can of soda...Ch. 2.7 - 2.16 Beginning from rest, an object of mass 200 kg...Ch. 2.7 - 2.17 Jack, who weighs 150 lbf, runs 5 miles in 43...Ch. 2.7 - 2.18 An object initially at an elevation of 5 m...Ch. 2.7 - 2.19 An object of mass 10 kg, initially at rest,...Ch. 2.7 - 2.20 An object initially at rest experiences a...Ch. 2.7 - 2.21 The drag force, Fd, imposed by the...Ch. 2.7 - 2.22 A major force opposing the motion of a...Ch. 2.7 - 2.23 The two major forces opposing the motion of a...Ch. 2.7 - 2.24 Measured data for pressure versus volume...Ch. 2.7 - 2.25 Measured data for pressure versus volume...Ch. 2.7 - 2.26 A gas in a piston-cylinder assembly undergoes...Ch. 2.7 - 2.27 Carbon dioxide (CO2) gas within a...Ch. 2.7 - 2.28 A gas in a piston-cylinder assembly undergoes...Ch. 2.7 - 2.29 Nitrogen (N2) gas within a piston-cylinder...Ch. 2.7 - 2.30 Oxygen (O2) gas within a piston-cylinder...Ch. 2.7 - 2.31 A closed system consisting of 14.5 lb of air...Ch. 2.7 - 2.32 Air contained within a piston-cylinder...Ch. 2.7 - 2.33 A gas contained within a piston-cylinder...Ch. 2.7 - 2.34 Carbon monoxide gas (CO) contained within a...Ch. 2.7 - 2.35 Air contained within a piston-cylinder...Ch. 2.7 - 2.36 The belt sander shown in Fig. P2.36 has a...Ch. 2.7 - 2.37 A 0.15-m-diameter pulley turns a belt...Ch. 2.7 - 2.38 A 10-V battery supplies a constant current of...Ch. 2.7 - 2.39 An electric heater draws a constant current...Ch. 2.7 - 2.40 A car magazine article states that the power...Ch. 2.7 - 2.41 The pistons of a V-6 automobile engine...Ch. 2.7 - 2.42 Figure P2.42 shows an object whose mass is 5...Ch. 2.7 - Prob. 43P Ch. 2.7 - 2.44 A soap film is suspended on a wire frame, as...Ch. 2.7 - 2.45 As shown in Fig. P2.45, a spring having an...Ch. 2.7 - 2.46 A fan forces air over a computer circuit...Ch. 2.7 - 2.47 As shown in Fig. P2.47, the 6-in.-thick...Ch. 2.7 - 2.48 As shown in Fig. P2.48, an oven wall consists...Ch. 2.7 - 2.49 A composite plane wall consists of a...Ch. 2.7 - 2.50 A composite plane wall consists of a...Ch. 2.7 - 2.51 An insulated frame wall of a house has an...Ch. 2.7 - 2.52 Complete the following exercise using heat...Ch. 2.7 - Prob. 53P Ch. 2.7 - Prob. 54P Ch. 2.7 - 2.55 The outer surface of the grill hood shown in...Ch. 2.7 - 2.56 Each line of the following table gives data...Ch. 2.7 - 2.57 Each line of the following table gives data,...Ch. 2.7 - 2.58 A closed system of mass 10 kg undergoes a...Ch. 2.7 - Prob. 59P Ch. 2.7 - 2.60 A gas contained in a piston−cylinder assembly...Ch. 2.7 - 2.61 A gas contained within a piston−cylinder...Ch. 2.7 - 2.62 An electric motor draws a current of 10 amp...Ch. 2.7 - 2.63 As shown in Fig. P2.63, the outer surface of...Ch. 2.7 - 2.64 One kg of Refrigerant 22, initially at p1 =...Ch. 2.7 - 2.65 A gas is contained in a vertical...Ch. 2.7 - 2.66 A gas undergoes a process in a...Ch. 2.7 - 2.67 Four kilograms of carbon monoxide (CO) is...Ch. 2.7 - 2.68 Helium gas is contained in a closed rigid...Ch. 2.7 - 2.69 Steam in a piston−cylinder assembly undergoes...Ch. 2.7 - 2.70 Air expands adiabatically in a...Ch. 2.7 - 2.71 A vertical piston−cylinder assembly with a...Ch. 2.7 - 2.72 Gaseous CO2 is contained in a vertical...Ch. 2.7 - 2.73 Figure P2.73 shows a gas contained in a...Ch. 2.7 - 2.74 The following table gives data, in kJ, for a...Ch. 2.7 - 2.75 The following table gives data, in Btu, for a...Ch. 2.7 - 2.76 Figure P2.76 shows a power cycle executed by...Ch. 2.7 - 2.77 A gas within a piston−cylinder assembly...Ch. 2.7 - 2.78 A gas within a piston-cylinder assembly...Ch. 2.7 - 2.79 A gas undergoes a cycle in a piston-cylinder...Ch. 2.7 - 2.80 As shown in Fig. P2.80, a gas within a...Ch. 2.7 - Prob. 81P Ch. 2.7 - Prob. 82P Ch. 2.7 - Prob. 83P Ch. 2.7 - Prob. 84P Ch. 2.7 - 2.85 A concentrating solar collector system, as...Ch. 2.7 - Prob. 86P Ch. 2.7 - Prob. 87P Ch. 2.7 - Prob. 88P Ch. 2.7 - 2.89 A refrigeration cycle operating as shown in...Ch. 2.7 - Prob. 90P Ch. 2.7 - Prob. 91P Ch. 2.7 - Prob. 92P Ch. 2.7 - Prob. 93P Ch. 2.7 - Prob. 94P Ch. 2.7 - 2.95 A heat pump maintains a dwelling at 688F....Ch. 2.7 - 2.96 A heat pump cycle delivers energy by heat...

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