Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
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Chapter 4.5, Problem 88P
An electronic device dissipating 25 W has a mass of 20 g and a specific heat of 850 J/kg·°C. The device is lightly used, and it is on for 5 min and then off for several hours, during which it cools to the ambient temperature of 25°C. Determine the highest possible temperature of the device at the end of the 5-min operating period. What would your answer be if the device were attached to a 0.5-kg aluminum heat sink? Assume the device and the heat sink to be nearly isothermal.
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Chapter 4 Solutions
Thermodynamics: An Engineering Approach
Ch. 4.5 - Is the boundary work associated with...Ch. 4.5 - On a P-V diagram, what does the area under the...Ch. 4.5 - An ideal gas at a given state expands to a fixed...Ch. 4.5 - Calculate the total work, in kJ, for process 13...Ch. 4.5 - Calculate the total work, in Btu, produced by the...Ch. 4.5 - Nitrogen at an initial state of 300 K, 150 kPa,...Ch. 4.5 - The volume of 1 kg of helium in a pistoncylinder...Ch. 4.5 - A pistoncylinder device with a set of stops...Ch. 4.5 - A mass of 5 kg of saturated water vapor at 150 kPa...Ch. 4.5 - A frictionless pistoncylinder device contains 16...
Ch. 4.5 - 1 m3 of saturated liquid water at 200C is expanded...Ch. 4.5 - Argon is compressed in a polytropic process with n...Ch. 4.5 - A gas is compressed from an initial volume of 0.42...Ch. 4.5 - A mass of 1.5 kg of air at 120 kPa and 24C is...Ch. 4.5 - During some actual expansion and compression...Ch. 4.5 - A frictionless pistoncylinder device contains 5 kg...Ch. 4.5 - During an expansion process, the pressure of a gas...Ch. 4.5 - A pistoncylinder device initially contains 0.4 kg...Ch. 4.5 - A pistoncylinder device contains 0.15 kg of air...Ch. 4.5 - Determine the boundary work done by a gas during...Ch. 4.5 - 1 kg of water that is initially at 90C with a...Ch. 4.5 - An ideal gas undergoes two processes in a...Ch. 4.5 - A pistoncylinder device contains 50 kg of water at...Ch. 4.5 - Prob. 26PCh. 4.5 - A closed system like that shown in Fig. P427E is...Ch. 4.5 - A rigid container equipped with a stirring device...Ch. 4.5 - Complete each line of the following table on the...Ch. 4.5 - A substance is contained in a well-insulated rigid...Ch. 4.5 - A 0.5-m3rigid tank contains refrigerant-134a...Ch. 4.5 - A 20-ft3 rigid tank initially contains saturated...Ch. 4.5 - A rigid 10-L vessel initially contains a mixture...Ch. 4.5 - A rigid 1-ft3 vessel contains R-134a originally at...Ch. 4.5 - A pistoncylinder device contains 5 kg of...Ch. 4.5 - A pistoncylinder device contains 0.5 lbm of water...Ch. 4.5 - 2 kg of saturated liquid water at 150C is heated...Ch. 4.5 - An insulated pistoncylinder device contains 5 L of...Ch. 4.5 - A 40-L electrical radiator containing heating oil...Ch. 4.5 - Steam at 75 kPa and 8 percent quality is contained...Ch. 4.5 - A pistoncylinder device initially contains 0.6 m3...Ch. 4.5 - An insulated tank is divided into two parts by a...Ch. 4.5 - Two tanks (Tank A and Tank B) are separated by a...Ch. 4.5 - Is the energy required to heat air from 295 to 305...Ch. 4.5 - A fixed mass of an ideal gas is heated from 50 to...Ch. 4.5 - A fixed mass of an ideal gas is heated from 50 to...Ch. 4.5 - A fixed mass of an ideal gas is heated from 50 to...Ch. 4.5 - Is the relation u = mcv,avgT restricted to...Ch. 4.5 - Is the relation h = mcp,avgT restricted to...Ch. 4.5 - What is the change in the internal energy, in...Ch. 4.5 - Neon is compressed from 100 kPa and 20C to 500 kPa...Ch. 4.5 - What is the change in the enthalpy, in kJ/kg, of...Ch. 4.5 - A mass of 10 g of nitrogen is contained in the...Ch. 4.5 - Determine the internal energy change u of...Ch. 4.5 - Determine the enthalpy change h of oxygen, in...Ch. 4.5 - Is it possible to compress an ideal gas...Ch. 4.5 - Nitrogen in a rigid vessel is cooled by rejecting...Ch. 4.5 - Nitrogen at 100 psia and 300F in a rigid container...Ch. 4.5 - A pistoncylinder device containing carbon-dioxide...Ch. 4.5 - A 3-m3 rigid tank contains hydrogen at 250 kPa and...Ch. 4.5 - 1 kg of oxygen is heated from 20 to 120C....Ch. 4.5 - A 10-ft3 tank contains oxygen initially at 14.7...Ch. 4.5 - A 4-m 5-m 7-m room is heated by the radiator of...Ch. 4.5 - An insulated rigid tank is divided into two equal...Ch. 4.5 - An ideal gas contained in a pistoncylinder device...Ch. 4.5 - A 4-m 5-m 6-m room is to be heated by a...Ch. 4.5 - An insulated pistoncylinder device initially...Ch. 4.5 - Argon is compressed in a polytropic process with n...Ch. 4.5 - An insulated pistoncylinder device contains 100 L...Ch. 4.5 - Air is contained in a variable-load pistoncylinder...Ch. 4.5 - A mass of 15 kg of air in a pistoncylinder device...Ch. 4.5 - Prob. 73PCh. 4.5 - A pistoncylinder device contains 2.2 kg of...Ch. 4.5 - A pistoncylinder device contains 4 kg of argon at...Ch. 4.5 - A spring-loaded pistoncylinder device contains 5...Ch. 4.5 - Prob. 78PCh. 4.5 - Prob. 79PCh. 4.5 - A 1-kg block of iron is heated from 25 to 75C....Ch. 4.5 - The state of liquid water is changed from 50 psia...Ch. 4.5 - During a picnic on a hot summer day, all the cold...Ch. 4.5 - An ordinary egg can be approximated as a...Ch. 4.5 - Consider a 1000-W iron whose base plate is made of...Ch. 4.5 - Stainless steel ball bearings ( = 8085 kg/m3 and...Ch. 4.5 - In a production facility, 1.6-in-thick 2-ft 2-ft...Ch. 4.5 - Long cylindrical steel rods ( = 7833 kg/m3 and cp...Ch. 4.5 - An electronic device dissipating 25 W has a mass...Ch. 4.5 - Prob. 90PCh. 4.5 - Prob. 91PCh. 4.5 - Is the metabolizable energy content of a food the...Ch. 4.5 - Is the number of prospective occupants an...Ch. 4.5 - Prob. 94PCh. 4.5 - Prob. 95PCh. 4.5 - Prob. 96PCh. 4.5 - Consider two identical 80-kg men who are eating...Ch. 4.5 - A 68-kg woman is planning to bicycle for an hour....Ch. 4.5 - A 90-kg man gives in to temptation and eats an...Ch. 4.5 - A 60-kg man used to have an apple every day after...Ch. 4.5 - Consider a man who has 20 kg of body fat when he...Ch. 4.5 - Consider two identical 50-kg women, Candy and...Ch. 4.5 - Prob. 103PCh. 4.5 - Prob. 104PCh. 4.5 - Prob. 105PCh. 4.5 - Prob. 106PCh. 4.5 - Prob. 107PCh. 4.5 - Prob. 108PCh. 4.5 - Prob. 109RPCh. 4.5 - Prob. 110RPCh. 4.5 - Prob. 111RPCh. 4.5 - Prob. 112RPCh. 4.5 - Prob. 113RPCh. 4.5 - Consider a pistoncylinder device that contains 0.5...Ch. 4.5 - Prob. 115RPCh. 4.5 - Air in the amount of 2 lbm is contained in a...Ch. 4.5 - Air is expanded in a polytropic process with n =...Ch. 4.5 - Nitrogen at 100 kPa and 25C in a rigid vessel is...Ch. 4.5 - Prob. 119RPCh. 4.5 - A mass of 3 kg of saturated liquidvapor mixture of...Ch. 4.5 - A mass of 12 kg of saturated refrigerant-134a...Ch. 4.5 - Prob. 122RPCh. 4.5 - A pistoncylinder device contains helium gas...Ch. 4.5 - Prob. 124RPCh. 4.5 - Prob. 125RPCh. 4.5 - Prob. 126RPCh. 4.5 - Prob. 127RPCh. 4.5 - Water is boiled at sea level in a coffeemaker...Ch. 4.5 - The energy content of a certain food is to be...Ch. 4.5 - Prob. 130RPCh. 4.5 - An insulated pistoncylinder device initially...Ch. 4.5 - An insulated rigid tank initially contains 1.4 kg...Ch. 4.5 - In order to cool 1 ton of water at 20C in an...Ch. 4.5 - A 0.3-L glass of water at 20C is to be cooled with...Ch. 4.5 - A well-insulated 3-m 4m 6-m room initially at 7C...Ch. 4.5 - Prob. 137RPCh. 4.5 - Prob. 138RPCh. 4.5 - Prob. 140RPCh. 4.5 - A pistoncylinder device initially contains 0.35 kg...Ch. 4.5 - Two 10-ft3 adiabatic tanks are connected by a...Ch. 4.5 - Prob. 143RPCh. 4.5 - Prob. 144RPCh. 4.5 - A 3-m3 rigid tank contains nitrogen gas at 500 kPa...Ch. 4.5 - A 0.5-m3 rigid tank contains nitrogen gas at 600...Ch. 4.5 - A well-sealed room contains 60 kg of air at 200...Ch. 4.5 - A room contains 75 kg of air at 100 kPa and 15C....Ch. 4.5 - Prob. 149FEPCh. 4.5 - A pistoncylinder device contains 5 kg of air at...Ch. 4.5 - Prob. 151FEPCh. 4.5 - A 2-kW electric resistance heater submerged in 5...Ch. 4.5 - Prob. 153FEPCh. 4.5 - 1.5 kg of liquid water initially at 12C is to be...Ch. 4.5 - Prob. 155FEPCh. 4.5 - An ordinary egg with a mass of 0.1 kg and a...Ch. 4.5 - Prob. 157FEPCh. 4.5 - A 6-pack of canned drinks is to be cooled from 18C...Ch. 4.5 - Prob. 159FEPCh. 4.5 - An ideal gas has a gas constant R = 0.3 kJ/kgK and...Ch. 4.5 - A pistoncylinder device contains an ideal gas. The...
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