1-1
SOLUTIONS MANUAL
Thermodynamics: An Engineering Approach
10th Edition
Yunus A. Çengel, Michael A. Boles, Mehmet Kanoğlu
McGraw-Hill, 2023
Chapter 1
INTRODUCTION AND BASIC CONCEPTS
CYU - CheckYour Understanding
CYU 1-1■Check Your Understanding
CYU 1-1.1 Choose the wrong statement about the first law of thermodynamics.
(a) During an interaction, energy can change from one form to another.
(b) During an interaction, the total amount of energy remains constant.
(c) Energy can be destroyed but it cannot be created.
(d) Energy is a thermodynamic property.
(e) A system with more energy input than output will gain energy.
Answer: (c) Energy can be destroyed but it cannot be created.
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, 1-2
CYU 1-1.2 Which statement best expresses the second law of thermodynamics?
(a) The temperature of a well-sealed room increases when a fan in the room is turned on.
(b) A cup of cool coffee in a warm room never gets hot by itself.
(c) Heat is generated when there is friction between two surfaces.
(d) A household refrigerator supplies heat to the kitchen when operating.
(e) A person who has a smaller energy input than output will lose weight.
Answer: (b) A cup of cool coffee in a warm room never gets hot by itself.
CYU 1-2■Check Your Understanding
CYU 1-2.1 Which of the following is not a correct unit for work?
(a) kg · 𝑚/𝑠 2
(b) Nm
(c) kPa · 𝑚3
(d) kJ
(e) kWh
Answer:(a) kg · 𝑚/𝑠 2
CYU 1-2.2 Using unit considerations, select the correct equations.
I. Mass = Force Acceleration
II. Work = Force Distance
III. Work = Power Time
IV. Density = Mass Volume
(a) I and II
(b) I and III
(c) II and III
(d) I, II, and III
(e) II, III, and IV
Answer: (c) II and III
CYU 1-2.3 What is the weight of 10 kg?
(a) 10 N
(b) 10 lbf
(c) 9.8 N
(d) 98 N
(e) 322 lbf
Answer: (d) 98 N
𝑊 = mg = (10 kg)(9.8 𝑚/𝑠 2 ) = 98 kg · 𝑚/𝑠 2 = 98 𝑁
2
since 1 𝑁 = 1 kg · 𝑚/𝑠
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, 1-3
CYU 1-3■ Check Your Understanding
CYU 1-3.1 Choose the wrong statement regarding systems and control volumes.
(a) The mass or region outside the system is called the surroundings.
(b) The real or imaginary surface that separates the system from its surroundings is called the boundary.
(c) The boundary has zero thickness.
(d) The boundary can neither contain any mass nor occupy any volume in space.
(e) The boundary of a system is fixed; it cannot move.
Answer: (e) The boundary of a system is fixed; it cannot move.
CYU 1-3.2 Choose the wrong statement regarding systems and control volumes.
(a) Both mass and energy can cross the boundary of a control volume.
(b) Mass cannot enter or leave a closed system but energy can.
(c) Mass can enter or leave an isolated system but energy cannot.
(d) The boundaries of a control volume can be real or imaginary.
(e) The volume of a closed system does not have to be fixed.
Answer: (c) Mass can enter or leave an isolated system but energy cannot.
CYU 1-4■Check Your Understanding
CYU 1-4.1 Which properties are intensive?
I. Volume,𝑚3
II. Density, kg/𝑚3
III. Temperature, C
IV. Pressure, kPa
(a) II and III
(b) III and IV
(c) I, II and III
(d) II, III, and IV
(e) I, II, III, and IV
Answer: (d) II, III, and IV
CYU 1-5■Check Your Understanding
CYU 1-5.1 A 1 − 𝑚3tank contains 0.5 kg of a gas. What is the density (inkg/𝑚3) and specific volume (in𝑚3 /𝑘𝑔) of the
fluid, respectively?
(a) 1, 0.5
(b) 0.5, 1
(c) 0.5, 2
(d) 2, 0.5
(e) 0.5, 0.5
Answer: (c) 0.5, 2
rho = 𝑚/𝑉 = (0.5 kg)/(1 𝑚3 ) = 0.5 kg/𝑚3
𝑣 = 𝑉/𝑚 = (1 𝑚3 )/(0.5 kg) = 2 𝑚3 /kg
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, 1-4
CYU 1-5.2 What is the specific volume of a fluid whose specific gravity is 1.25?
(a) 1.25 𝑚3/kg
(b) 1250 𝑚3 /kg
(c) 1/1.25 𝑚3 /kg
(d) 1/1250 𝑚3/kg
(e) 1.25 𝑚3/kg
Answer: (d) 1/1250 𝑚3 /kg
rho = SG rhow = (1.25)(1000 kg/𝑚3) = 1250 kg/𝑚3
𝑣 = 1/rho = 1/(1250 kg/𝑚3 ) = 1/1250 𝑚3 /kg
CYU 1-5.3 What is the specific weight of a fluid whose specific gravity is 1?
(a) 1 𝑁/𝑚3
(b) 9.8 𝑁/𝑚3
(c) 10 𝑁/𝑚3
(d) 980 𝑁/𝑚3
(e) 9800 𝑁/𝑚3
Answer: (e) 9800 𝑁/𝑚3
SW = rhog = (1000 kg/𝑚3 )(9.8 𝑚/𝑠 2 ) = 9800 kg · 𝑚/𝑚3 · 𝑠 2 = 9800 𝑁/𝑚3
since 1 𝑁 = 1 kg · 𝑚/𝑠 2
CYU 1-6■ Check Your Understanding
CYU 1-6.1 Choose the wrong statement regarding state and equilibrium.
(a) A set of properties completely describes the state of a system.
(b) At a given state, all the properties of a system have fixed values.
(c) The state of a system only changes if the values of at least two properties change.
(d) In an equilibrium state there are no driving forces within the system.
(e) A system in equilibrium experiences no changes when it is isolated from its surroundings.
Answer: (c) The state of a system only changes if the values of at least two properties change.
CYU 1-8■ Check Your Understanding
CYU 1-8.1 The initial and final temperatures of an object are 20C and 300 K. The temperature change of the object is
(a) 27C
(b) (b) 20C
(c) 7C
(d) 300 K
(e) 280 K
Answer: (c) 7C
T1 = 20C
T2 = 300 K = 27C
dT= 27 – 20 = 7C
CYU 1-8.2 A temperature change of 10C is equal to
© MCGRAW HILL LLC. ALL RIGHTS RESERVED. NO REPRODUCTION OR DISTRIBUTION WITHOUT THE PRIOR
WRITTEN CONSENT OF MCGRAW HILL LLC.
SOLUTIONS MANUAL
Thermodynamics: An Engineering Approach
10th Edition
Yunus A. Çengel, Michael A. Boles, Mehmet Kanoğlu
McGraw-Hill, 2023
Chapter 1
INTRODUCTION AND BASIC CONCEPTS
CYU - CheckYour Understanding
CYU 1-1■Check Your Understanding
CYU 1-1.1 Choose the wrong statement about the first law of thermodynamics.
(a) During an interaction, energy can change from one form to another.
(b) During an interaction, the total amount of energy remains constant.
(c) Energy can be destroyed but it cannot be created.
(d) Energy is a thermodynamic property.
(e) A system with more energy input than output will gain energy.
Answer: (c) Energy can be destroyed but it cannot be created.
© MCGRAW HILL LLC. ALL RIGHTS RESERVED. NO REPRODUCTION OR DISTRIBUTION WITHOUT THE PRIOR
WRITTEN CONSENT OF MCGRAW HILL LLC.
, 1-2
CYU 1-1.2 Which statement best expresses the second law of thermodynamics?
(a) The temperature of a well-sealed room increases when a fan in the room is turned on.
(b) A cup of cool coffee in a warm room never gets hot by itself.
(c) Heat is generated when there is friction between two surfaces.
(d) A household refrigerator supplies heat to the kitchen when operating.
(e) A person who has a smaller energy input than output will lose weight.
Answer: (b) A cup of cool coffee in a warm room never gets hot by itself.
CYU 1-2■Check Your Understanding
CYU 1-2.1 Which of the following is not a correct unit for work?
(a) kg · 𝑚/𝑠 2
(b) Nm
(c) kPa · 𝑚3
(d) kJ
(e) kWh
Answer:(a) kg · 𝑚/𝑠 2
CYU 1-2.2 Using unit considerations, select the correct equations.
I. Mass = Force Acceleration
II. Work = Force Distance
III. Work = Power Time
IV. Density = Mass Volume
(a) I and II
(b) I and III
(c) II and III
(d) I, II, and III
(e) II, III, and IV
Answer: (c) II and III
CYU 1-2.3 What is the weight of 10 kg?
(a) 10 N
(b) 10 lbf
(c) 9.8 N
(d) 98 N
(e) 322 lbf
Answer: (d) 98 N
𝑊 = mg = (10 kg)(9.8 𝑚/𝑠 2 ) = 98 kg · 𝑚/𝑠 2 = 98 𝑁
2
since 1 𝑁 = 1 kg · 𝑚/𝑠
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WRITTEN CONSENT OF MCGRAW HILL LLC.
, 1-3
CYU 1-3■ Check Your Understanding
CYU 1-3.1 Choose the wrong statement regarding systems and control volumes.
(a) The mass or region outside the system is called the surroundings.
(b) The real or imaginary surface that separates the system from its surroundings is called the boundary.
(c) The boundary has zero thickness.
(d) The boundary can neither contain any mass nor occupy any volume in space.
(e) The boundary of a system is fixed; it cannot move.
Answer: (e) The boundary of a system is fixed; it cannot move.
CYU 1-3.2 Choose the wrong statement regarding systems and control volumes.
(a) Both mass and energy can cross the boundary of a control volume.
(b) Mass cannot enter or leave a closed system but energy can.
(c) Mass can enter or leave an isolated system but energy cannot.
(d) The boundaries of a control volume can be real or imaginary.
(e) The volume of a closed system does not have to be fixed.
Answer: (c) Mass can enter or leave an isolated system but energy cannot.
CYU 1-4■Check Your Understanding
CYU 1-4.1 Which properties are intensive?
I. Volume,𝑚3
II. Density, kg/𝑚3
III. Temperature, C
IV. Pressure, kPa
(a) II and III
(b) III and IV
(c) I, II and III
(d) II, III, and IV
(e) I, II, III, and IV
Answer: (d) II, III, and IV
CYU 1-5■Check Your Understanding
CYU 1-5.1 A 1 − 𝑚3tank contains 0.5 kg of a gas. What is the density (inkg/𝑚3) and specific volume (in𝑚3 /𝑘𝑔) of the
fluid, respectively?
(a) 1, 0.5
(b) 0.5, 1
(c) 0.5, 2
(d) 2, 0.5
(e) 0.5, 0.5
Answer: (c) 0.5, 2
rho = 𝑚/𝑉 = (0.5 kg)/(1 𝑚3 ) = 0.5 kg/𝑚3
𝑣 = 𝑉/𝑚 = (1 𝑚3 )/(0.5 kg) = 2 𝑚3 /kg
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WRITTEN CONSENT OF MCGRAW HILL LLC.
, 1-4
CYU 1-5.2 What is the specific volume of a fluid whose specific gravity is 1.25?
(a) 1.25 𝑚3/kg
(b) 1250 𝑚3 /kg
(c) 1/1.25 𝑚3 /kg
(d) 1/1250 𝑚3/kg
(e) 1.25 𝑚3/kg
Answer: (d) 1/1250 𝑚3 /kg
rho = SG rhow = (1.25)(1000 kg/𝑚3) = 1250 kg/𝑚3
𝑣 = 1/rho = 1/(1250 kg/𝑚3 ) = 1/1250 𝑚3 /kg
CYU 1-5.3 What is the specific weight of a fluid whose specific gravity is 1?
(a) 1 𝑁/𝑚3
(b) 9.8 𝑁/𝑚3
(c) 10 𝑁/𝑚3
(d) 980 𝑁/𝑚3
(e) 9800 𝑁/𝑚3
Answer: (e) 9800 𝑁/𝑚3
SW = rhog = (1000 kg/𝑚3 )(9.8 𝑚/𝑠 2 ) = 9800 kg · 𝑚/𝑚3 · 𝑠 2 = 9800 𝑁/𝑚3
since 1 𝑁 = 1 kg · 𝑚/𝑠 2
CYU 1-6■ Check Your Understanding
CYU 1-6.1 Choose the wrong statement regarding state and equilibrium.
(a) A set of properties completely describes the state of a system.
(b) At a given state, all the properties of a system have fixed values.
(c) The state of a system only changes if the values of at least two properties change.
(d) In an equilibrium state there are no driving forces within the system.
(e) A system in equilibrium experiences no changes when it is isolated from its surroundings.
Answer: (c) The state of a system only changes if the values of at least two properties change.
CYU 1-8■ Check Your Understanding
CYU 1-8.1 The initial and final temperatures of an object are 20C and 300 K. The temperature change of the object is
(a) 27C
(b) (b) 20C
(c) 7C
(d) 300 K
(e) 280 K
Answer: (c) 7C
T1 = 20C
T2 = 300 K = 27C
dT= 27 – 20 = 7C
CYU 1-8.2 A temperature change of 10C is equal to
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WRITTEN CONSENT OF MCGRAW HILL LLC.
