Physics for Scientists and Engineers: Foundations and Connections
1st Edition
ISBN: 9781133939146
Author: Katz, Debora M.
Publisher: Cengage Learning
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Chapter 21, Problem 61PQ
To determine
The equilibrium temperature of the highway surface.
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In an electrically heated home, the temperature of the ground in contact with a concrete basement wall is 10.3 oC. The temperature at the inside surface of the wall is 18.1 oC. The wall is 0.14 m thick and has an area of 6.5 m2. Assume that one kilowatt hour of electrical energy costs $0.10. How many hours are required for one dollar's worth of energy to be conducted through the wall?
The thermal conductivities of human tissues vary greatly. Fat and skin have conductivities of about 0.20 W/m · K and 0.020 W/m · K respectively, while other tissues inside the body have conductivities of about 0.50 W/m · K. Assume that between the core region of the body and the skin surface lies a skin layer of 1.0 mm, fat layer of 0.50 cm, and 3.2 cm of other tissues.
(a) Find the R-factor for each of these layers, and the equivalent R-factor for all layers taken together, retaining two digits.
Rskin
m2 · K/W
Rfat
m2 · K/W
Rtissue
m2 · K/W
R
m2 · K/W
(b) Find the rate of energy loss when the core temperature is 37°C and the exterior temperature is 0°C. Assume that both a protective layer of clothing and an insulating layer of unmoving air are absent, and a body area of 2.0 m2. W
The thermal conductivities of human tissues vary greatly. Fat and skin have conductivities of about 0.20 W/m · K and 0.020 w/m · K respectively, while other tissues inside the body
have conductivities of about 0.50 W/m · K. Assume that between the core region of the body and the skin surface lies a skin layer of 1.0 mm, fat layer of 0.50 cm, and 3.2 cm of other
tissues.
(a) Find the R-factor for each of these layers, and the equivalent R-factor for all layers taken together, retaining two digits.
m² - K/W
Rskin
m² . K/W
Rfat
m² - K/W
Rtissue
|m² - K/W
R
(b) Find the rate of energy loss when the core temperature is 37°C and the exterior temperature is 0°C. Assume that both a protective layer of clothing and an insulating layer of
unmoving air are absent, and a body area of 2.0 m2.
Chapter 21 Solutions
Physics for Scientists and Engineers: Foundations and Connections
Ch. 21.2 - Incorrect. Heat is not contained in Texas. The...Ch. 21.3 - In each situation listed, an objects temperature...Ch. 21.4 - Prob. 21.3CECh. 21.4 - Prob. 21.4CECh. 21.7 - Prob. 21.5CECh. 21.7 - Prob. 21.6CECh. 21.7 - Prob. 21.7CECh. 21.7 - Prob. 21.8CECh. 21.7 - Prob. 21.9CECh. 21 - Prob. 1PQ
Ch. 21 - Prob. 2PQCh. 21 - You extend an impromptu invitation to a friend for...Ch. 21 - Prob. 4PQCh. 21 - Prob. 5PQCh. 21 - Prob. 6PQCh. 21 - Prob. 7PQCh. 21 - Prob. 8PQCh. 21 - Prob. 9PQCh. 21 - Prob. 10PQCh. 21 - Prob. 11PQCh. 21 - Prob. 12PQCh. 21 - Prob. 13PQCh. 21 - Prob. 14PQCh. 21 - Prob. 15PQCh. 21 - Prob. 16PQCh. 21 - Prob. 17PQCh. 21 - Prob. 18PQCh. 21 - Prob. 19PQCh. 21 - From Table 21.1, the specific heat of milk is 3.93...Ch. 21 - Prob. 21PQCh. 21 - Prob. 22PQCh. 21 - An ideal gas is confined to a cylindrical...Ch. 21 - Prob. 24PQCh. 21 - You place frozen soup (T = 17C) in a microwave...Ch. 21 - A 25-g ice cube at 0.0C is heated. After it first...Ch. 21 - Prob. 27PQCh. 21 - Prob. 28PQCh. 21 - Prob. 29PQCh. 21 - Prob. 30PQCh. 21 - Consider the latent heat of fusion and the latent...Ch. 21 - Prob. 32PQCh. 21 - Prob. 33PQCh. 21 - A thermodynamic cycle is shown in Figure P21.34...Ch. 21 - Prob. 35PQCh. 21 - Figure P21.36 shows a cyclic thermodynamic process...Ch. 21 - Figure P21.37 shows a PV diagram for a gas that is...Ch. 21 - Prob. 38PQCh. 21 - Prob. 39PQCh. 21 - Prob. 40PQCh. 21 - Prob. 41PQCh. 21 - Prob. 42PQCh. 21 - Prob. 43PQCh. 21 - Prob. 44PQCh. 21 - Figure P21.45 shows a cyclic process ABCDA for...Ch. 21 - Prob. 46PQCh. 21 - Prob. 47PQCh. 21 - Prob. 48PQCh. 21 - Prob. 49PQCh. 21 - Prob. 50PQCh. 21 - Prob. 51PQCh. 21 - Prob. 52PQCh. 21 - Prob. 53PQCh. 21 - Prob. 54PQCh. 21 - Prob. 55PQCh. 21 - You extend an impromptu invitation to a friend for...Ch. 21 - Prob. 57PQCh. 21 - Prob. 58PQCh. 21 - A lake is covered with ice that is 2.0 cm thick....Ch. 21 - A concerned mother is dressing her child for play...Ch. 21 - Prob. 61PQCh. 21 - Prob. 62PQCh. 21 - Prob. 63PQCh. 21 - Prob. 64PQCh. 21 - Prob. 65PQCh. 21 - Prob. 66PQCh. 21 - Prob. 67PQCh. 21 - Prob. 68PQCh. 21 - Three 100.0-g ice cubes initially at 0C are added...Ch. 21 - Prob. 70PQCh. 21 - Prob. 71PQCh. 21 - Prob. 72PQCh. 21 - Prob. 73PQCh. 21 - Prob. 74PQCh. 21 - Prob. 75PQCh. 21 - Prob. 76PQCh. 21 - Prob. 77PQCh. 21 - Prob. 78PQCh. 21 - How much faster does a cup of tea cool by 1C when...Ch. 21 - The PV diagram in Figure P21.80 shows a set of...Ch. 21 - Prob. 81PQCh. 21 - Prob. 82PQCh. 21 - Prob. 83PQCh. 21 - Prob. 84PQCh. 21 - Prob. 85PQ
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Heat Transfer: Crash Course Engineering #14; Author: CrashCourse;https://www.youtube.com/watch?v=YK7G6l_K6sA;License: Standard YouTube License, CC-BY