Physics For Scientists and Engineers
4th Edition
ISBN: 9780134391786
Author: Randall D. Knight
Publisher: PEARSON
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Chapter 19, Problem 37EAP
BIO human body. Model a head as a 20-cm-diameter, 20-cm-tall
cylinder with a flat top. If the body's surface temperature is 35°C,
what is the net rate of heat loss on a chilly 5°C day? All skin,
regardless of color, is effectively black in the infrared where the
radiation occurs, so use an emissivity of 0.95.
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Animal tissue helps prevent excessive heat loss by conduction. In species 1, the outer tissue has thermal conductivity k1, cross-sectional area A1, and thickness x1. In species 2, the outer tissue has thermal conductivity k2, cross-sectional area A2, and thickness x2. For the same difference between internal and external temperatures, how is the rate of heat loss in species 2 (P2) related to that in species 1 (P1)?
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P2 = (A1/A2) (x1/x2) (k2/k1) P1
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P2 = (A1/A2) (x2/x1) (k2/k1) P1
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A person is standing outdoors in the shade where the temperature is 21 °C. (a) What is the radiant energy absorbed per second by his head when it is covered with hair? The surface area of the hair (assumed to be flat) is 130 cm2 and its emissivity is 0.90. (b) What would be the radiant energy absorbed per second by the same person if he were bald and the emissivity of his head were 0.54?
A 880 cm X 1680 cm house is built on a 15.6 cm thick concrete slab of thermal conductivity 0.62 W/m.K.. If the ground temperature of the slab is 7.6ºC while the interior of the house is 21ºC.
Calculate the following:
a) The temperature difference in kelvin
Answer for part 1
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b) The temperature gradient (ΔT/Δx) in kelvin/metre
Answer for part 2
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c) The heat loss rate through the concrete slab in kilowatt
Answer for part 3
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Chapter 19 Solutions
Physics For Scientists and Engineers
Ch. 19 - Prob. 1CQCh. 19 - Do (a) temperature, (b) heat, and (c) thermal...Ch. 19 - Prob. 3CQCh. 19 - You need to raise the temperature of a gas by...Ch. 19 - Prob. 5CQCh. 19 - Prob. 6CQCh. 19 - FIGURE Q19.7 shows two different processes taking...Ch. 19 - FIGURE Q19.8 shows two different processes taking...Ch. 19 - The gas cylinder in FIGURE Q19.9 is a rigid...Ch. 19 - The gas cylinder in FIGURE Q19.10 is well...
Ch. 19 - The gas cylinder in FIGURE Q19.11 is well...Ch. 19 - How much work is done on the gas in the process...Ch. 19 - Prob. 2EAPCh. 19 - Prob. 3EAPCh. 19 - A 2000 cm3 container holds 0.10 mol of helium gas...Ch. 19 - Prob. 5EAPCh. 19 - Prob. 6EAPCh. 19 - Draw a first-law bar chart (see Figure 19.12) for...Ch. 19 - Draw a first-law bar chart (see Figure 19.12) for...Ch. 19 - 9. Draw a first-law bar chart (see Figure 19.12)...Ch. 19 - Prob. 10EAPCh. 19 - J of work are done on a system in a process that...Ch. 19 - How much heat energy must be added to a...Ch. 19 - Prob. 13EAPCh. 19 - Prob. 14EAPCh. 19 - Prob. 15EAPCh. 19 - Prob. 16EAPCh. 19 - One way you keep from overheating is by...Ch. 19 - Prob. 18EAPCh. 19 - Two cars collide head-on while each is traveling...Ch. 19 - An experiment measures the temperature of a 500 g...Ch. 19 - 30 g of copper pellets are removed from a 300°C...Ch. 19 - A 750 g aluminum pan is removed from the stove and...Ch. 19 - A 50.0 g thermometer is used to measure the...Ch. 19 - A 500 g metal sphere is heated to 300°C, then...Ch. 19 - A 65 cm3 block of iron is removed from an 800°C...Ch. 19 - Prob. 26EAPCh. 19 - A container holds 1.0 g of oxygen at a pressure of...Ch. 19 - The volume of a gas is halved during an adiabatic...Ch. 19 - Prob. 29EAPCh. 19 - Prob. 30EAPCh. 19 - Prob. 31EAPCh. 19 - Prob. 32EAPCh. 19 - Prob. 33EAPCh. 19 - Prob. 34EAPCh. 19 - Prob. 35EAPCh. 19 - What maximum power can be radiated by a...Ch. 19 - Radiation from the head is a major source of heat...Ch. 19 - Prob. 38EAPCh. 19 - Prob. 39EAPCh. 19 - Prob. 40EAPCh. 19 - Prob. 41EAPCh. 19 - Prob. 42EAPCh. 19 - Prob. 43EAPCh. 19 - The specific heat of most solids is nearly...Ch. 19 - Prob. 45EAPCh. 19 - Prob. 46EAPCh. 19 - Prob. 47EAPCh. 19 - Prob. 48EAPCh. 19 - .0 mol of gas are at 30°C and a pressure of 1.5...Ch. 19 - A 6.0-cm-diameter cylinder of nitrogen gas has a...Ch. 19 - Prob. 51EAPCh. 19 - An ideal-gas process is described by p = cV 1/2 ,...Ch. 19 - Prob. 53EAPCh. 19 - Prob. 54EAPCh. 19 - Prob. 55EAPCh. 19 - Prob. 56EAPCh. 19 - Prob. 57EAPCh. 19 - .10 mol of nitrogen gas follow the two processes...Ch. 19 - Prob. 59EAPCh. 19 - Prob. 60EAPCh. 19 - Prob. 61EAPCh. 19 - Prob. 62EAPCh. 19 - Prob. 63EAPCh. 19 - Prob. 64EAPCh. 19 - Prob. 65EAPCh. 19 - Prob. 66EAPCh. 19 - Prob. 67EAPCh. 19 - Prob. 68EAPCh. 19 - Prob. 69EAPCh. 19 - A cylindrical copper rod and an iron rod with...Ch. 19 - Prob. 71EAPCh. 19 - Prob. 72EAPCh. 19 - Prob. 73EAPCh. 19 - Prob. 74EAPCh. 19 - Prob. 75EAPCh. 19 - Prob. 76EAPCh. 19 - Prob. 77EAPCh. 19 - Prob. 78EAPCh. 19 - Prob. 79EAPCh. 19 - Prob. 80EAPCh. 19 - Prob. 81EAPCh. 19 - Prob. 82EAP
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