Essential college physics

696 Pages·2010·58.73 MB·English

by  Andrew F Rex, Richard Wolfson

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Brief Contents
VOLUME 1
Chapter 1 Measurements in Physics 1
Chapter 2 Motion in One Dimension 18
Chapter 3 Motion in Two Dimensions 41
Chapter 4 Force and Newtons Laws of Motion 65
Chapter 5 Work and Energy 94
Chapter 6 Momentum and Collisions 122
Chapter 7 Oscillations 147
Chapter 8 Rotational Motion 169
Chapter 9 Gravitation 199
Chapter 10 Solids and Fluids 221
Chapter 11 Waves and Sound 242
Chapter 12 Temperature, Thermal Expansion, and Ideal Gases 263
Chapter 13 Heat 283
Chapter 14 The Laws of Thermodynamics 304
VOLUME 2
Chapter 15 Electric Charges, Forces, and Fields 329
Chapter 16 Electric Energy, Potential, and Capacitors 355
Chapter 17 Electric Current, Resistance, and Circuits 377
Chapter 18 Magnetic Fields and Forces 403
Chapter 19 Electromagnetic Induction and Alternating Current 427
Chapter 20 Electromagnetic Waves and Special Relativity 453
Chapter 21 Geometrical Optics 480
Chapter 22 Wave Optics 510
Chapter 23 Modern Physics 531
Chapter 24 Atomic Physics 554
Chapter 25 Nuclear Physics 582
Chapter 26 A Universe of Particles 611
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Problem-Solving Strategies and Tactics
Volume 1 (pp. 1 328) contains Chapters 1 14
Volume 2 (pp. 329 634) contains Chapters 15 26
Chapter Problem-Solving Strategy Page
2 2.1 Solving Kinematics Problems with Constant Acceleration 32
3 3.1 Solving Projectile Motion Problems 54
4 4.1 Solving Dynamics Problems 75
5 5.1 The Work-Energy Theorem 104
5.2 Conservation of Mechanical Energy 109
6 6.1 Conservation of Momentum 127
8 8.1 Kinematics Problems with Constant Angular Acceleration 174
8.2 Mechanical Equilibrium 186
13 13.1 Heating,Melting,and Vaporizing 293
15 15.1 Finding the Net Force Due to Multiple Electric Charges 336
16 16.1 Networks of Capacitors 367
17 17.1 Networks of Resistors 388
Chapter Tactic Page
1 1.1 Unit Conversions 7
3 3.1 Vector Addition and Subtraction 46
4 4.1 Drawing Force Diagrams 67
11 11.1 Intensity Level and Decibels 251
14 14.1 The First Law of Thermodynamics 312
18 18.1 Drawing Vectors in Three Dimensions 406
19 19.1 Applying Lenzs Law 429
21 21.1 Image Formation by Concave Mirrors 484
21.2 Image Formation by Convex Lenses 492
ii
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C O L L E G E P H Y S I C S
Essential
FIRST EDITION
Andrew F. Rex Richard Wolfson
Volume 1
Chapters 1 14 University of Puget Sound Middlebury College
Addison-Wesley
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Jessica Lyons Formation ,four men jumping over a wall
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Credits and acknowledgments borrowed from other sources and reproduced,with permission,in
this textbook appear on p. C-1.
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Library of Congress Cataloging-in-Publication Data
Rex,Andrew F.,1956-
Essential college physics / Andrew F. Rex,Richard Wolfson. 1st ed.
p. cm.
Includes index.
ISBN-13:978-0-321-61116-1 (v. 1)
ISBN-10:0-321-61116-0 (v. 1)
ISBN-13:978-0-321-61117-8 (v. 2)
ISBN-10:0-321-61117-9 (v. 2)
1. Physics Textbooks. I. Wolfson,Richard. II. Title.
QC23.2.R49 2009
530 dc22 2009024991
ISBN 10:0-321-61116-0; ISBN 13:978-0-321-61116-1 (Student edition Volume 1)
ISBN 10:0-321-66665-8; ISBN 13:978-0-321-66665-9 (Professional copy Volume 1)
1 2 3 4 5 6 7 8 9 10 CRK 13 12 11 10 09
Manfactured in the United States of America.
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About the Authors
Andrew F. Rex
Andrew F. Rex has been professor of physics at the University of Puget Sound since 1982.
He frequently teaches the College Physics course, so he has a deep sense of student and
instructor challenges. He is the author of several textbooks,including Modern Physics for
Scientists and Engineers and Integrated Physics and Calculus. In addition to textbook
writing,he studies foundations of the second law of thermodynamics,which has led to the
publication of several papers and the widely acclaimed book Maxwells Demon:Entropy,
Information,Computing.
ck
Merri
Tad
Richard Wolfson
Richard Wolfson has been professor of physics at Middlebury College for more than
25years. In addition to his textbooks,Essential University Physics,Physics for Scientists
and Engineers,and Energy,Environment,and Climate,he has written two science books
for general audiences: Nuclear Choices: A Citizens Guide to Nuclear Technology, and
Simply Einstein: Relativity Demystified. His video courses for the Teaching Company
include Physics in Your Life and Einsteins Relativity and the Quantum Revolution:
Modern Physics for Non-Scientists.
v
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Preface to the Instructor
During the three decades we have been teaching physics,algebra-based physics textbooks
have grown in length,complexity,and price. Weve reached the point where textbooks can
be overwhelming to students, many of whom are taking physics as a requirement for
another major or profession and will never take another physics class. And yet,weve also
seen many students in the algebra-based course who are eager to learn how physics
explains what they see in their everyday lives, how it connects to other disciplines, and
how exciting new ideas in physics can be.
A Concise and Focused Book
The first thing you ll notice about this book is that its more concise than most algebra-
based textbooks. We believe it is possible to provide a shorter,more focused text that better
addresses the learning needs of todays students while more effectively guiding them
through the mastery of physics. The language is concise and engaging without sacrificing
depth. Brevity needn t come at the expense of student learning! Weve designed our text
from the ground up to be concise and focused,rather than cutting down a longer book. Stu-
dents will find the resulting book less intimidating and easier to use,with well coordinated
narrative,instructional art program,and worked examples.
A Connected Approach
In addition to making the volume of the book less overwhelming,weve stressed connec-
tions,to reinforce students understanding and to combat the preconception that physics is
just a long list of facts and formulas.
Connecting ideas The organization of topics and the narrative itself stress the connec-
tions between ideas. Whenever possible,the narrative points directly to a worked example
or to the next section. A worked example can serve as a bridge,not only to the preceding
material it is being used to illustrate,but also forward by introducing a new idea that is then
explicated in the following section. These bridges work both ways; the text is always look-
ing forward and back to exploit the rich trail of connections that exist throughout physics.
Complete edition Volumes 1 2
* Connecting physics with the real world Instead of simply stating the facts of physics
(shrinkwrapped) (ISBN 978-0-
and backing them up with examples,the book develops some key concepts from observa-
321-59854-7):Chapters 1 26
tions of real-world phenomena. This approach helps students to understand what physics is
* Volume 1 (ISBN 978-0-321- and how it relates to their lives. In addition,numerous examples and applications help stu-
61116-1):Chapters 1 14 dents explore the ideas of physics as they relate to the real world. Connections are made to
Volume 2 (ISBN 978-0-321- phenomena that will engage the students applications from everyday life (heating a
*
61117-8):Chapters 15 26 home, the physics of flight, DVDs, hybrid vehicles, and many more), from biomedicine
(pacemakers, blood flow, cell membranes, medical imaging), and from cutting-edge
Complete edition Volumes 1 2
*
research in science and technology (superconductivity, nanotechnology, ultracapacitors).
(shrinkwrapped) with Master-
These applications can be used to motivate interest in particular topics in physics,or they
ingPhysicsTM(ISBN 978-0-321-
might emerge from learning a new physics topic. One thing leads to another. What results
59856-1):Chapters 1 26
is a continuous story of physics,seen as a seamless whole rather than an encyclopedia of
Volume 1 with Mastering-
* facts to be memorized.
PhysicsTM(ISBN 978-0-321-
61118-5):Chapters 1 14 Connecting words and math In the same way, we stress the connections between the
ideas of physics and their mathematical expression. Equations are statements about
Volume 2 with Mastering-
*
physics sentences,really not magical formulae. In algebra-based physics,its important
PhysicsTM(ISBN 978-0-321-
to stress the basics but not the myriad details that cloud the issues for those new to the sub-
61119-2):Chapters 15 26
ject. Weve reduced the number of enumerated equations,to make the essentials clearer.
vi
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Preface to the Instructor vii
Connecting with how students learn Conceptual worked examples and end-of-chapter
problems are designed to help students explore and master the qualitative ideas developed
in the text. Some conceptual examples are linked with numerical examples that precede or
follow them, linking qualitative and quantitative reasoning skills. Follow-up exercises to
worked examples ( Making the Connection ) prompt students to explore further, while
Got It? questions (short concept-check questions found at the end of text sections) help
ensure a key idea is grasped before the student moves on.
Students benefit from a structured learning path clear goals set out at the start, rein-
forcement of new ideas throughout,and a strategic summary to wrap up. With these aids in
place,students build a solid foundation of understanding. We therefore carefully structure
the chapters with learning goals, Reviewing new concepts reminders,and visual chapter
summaries.
Connecting with how students use their textbook Many students find using a textbook
to be a chore, either because English is not their first language or because their reading
skills are weak or their time limited. Even students who read with ease prefer their expla-
nations lucid and brief,and they expect key information to be easy to find. Our goal,there-
fore,is a text that is clear,concise,and focused,with easy-to-find reference material,tips,
and examples. The manageable size of the book makes it less intimidating to open and
easier to take to class.
To complement verbal explanations in the text,the art program puts considerable infor-
mation directly on the art in the form of explanatory labels and authors voice commen-
tary. Thus,students can use the text and art as parallel,complementary ways to understand
the material. The text tells them more, but often the illustrations will prove more memo-
rable and will serve as keys for recalling information. In addition,a student who has diffi-
culty with the text can turn to the art for help.
Connecting the chapters with homework After reading a chapter, students need to be
able to reason their way through homework problems with some confidence that they will
succeed. A textbook can help by consistently demonstrating and modeling how an expert
goes about solving a problem,by giving clear tips and tactics,and by providing opportuni-
ties for practice. Given how important it is for students to become proficient at solving
problems,a detailed explanation of how our textbook will help them is provided below.
Problem-Solving Strategies
Worked examples are presented consistently in a three-step approach that provides a model
for students:
Organize and Plan The first step is to gain a clear picture of what the problem is asking.
Then students gather information they need to address the problem,based on information
presented in the text and considering similarities with earlier problems, both conceptual
and numerical. If a student sketch is needed to help understand the physical situation,this
is the place for it. Any known quantities that will be needed to calculate the answer or
answers are gathered at the end of this step.
Solve The plan is put into action, and the required steps carried out to reach a final
answer. Computations are presented in enough detail for the student to see a clear path
from start to finish.
Reflect There are many things that a student might consider here. Most important is
whether the answer is reasonable, in the context of either the problem or a similar known
situation. This is the place to see whether units are correct or to check that symbolic answers
reduce to sensible results in obvious special cases. The student may reflect on connections
to other solved problems or real-life situations. Sometimes solving a problem raises a new
question,which can lead naturally to another example,the next section,or the next chapter.
Conceptual examples follow a simpler two-step approach: Solve and Reflect. As with
the worked examples,the Reflect step is often used to point out important connections.
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viii Preface to the Instructor
Worked examples are followed by Making the Connection, a new problem related to
the one just solved,which serves as a further bridge to earlier material or the next section
of text. Answers to Making the Connection are provided immediately,and thus they also
serve as good practice problems getting a second example for the price of one.
Strategy boxes follow the three-step approach that parallels the approach in worked
examples. These give students additional hints about what to do in each of the three steps.
Tactic boxes give additional problem-solving tools,outside the three-step system.
End-of-Chapter Problems
There are three types of problems:
1. Conceptual questions, like the conceptual worked examples, ask the students to
think about the physics and reason without using numbers.
2. Multiple-choice problemsserve three functions. First,they prepare students for their
exams,in cases where instructors use that format. Second,those students who take
this course in preparation for the MCAT exam or other standardized exam will
get some needed practice. Third, they offer more problem-solving practice for all
students.
3. Problemsinclude a diversity of problem types,as well as a range of difficulty,with
difficulty levels marked by one, two, or three boxes. Problems are numerous
enough to span an appropriate range of difficulty, from confidence builders to
challenge problems. Most problems are listed under a particular section number in
the chapter. General problems at the end are not tied to any section. These problem
sets include multi-concept problems that require using concepts and techniques from
more than one section or from an earlier chapter.
Organization of Topics
The organization of topics should be familiar to anyone who has taught College Physics.
The combined Volumes 1 and 2 cover a full-year course in algebra-based physics,divided
into either two semesters or three quarters.
Volume 1: Following the introductory Chapter 1, the remainder of Volume 1 is devoted
to mechanics of particles and systems, including one chapter each on gravitation, fluids,
and waves (including sound). Volume 1 concludes with a three-chapter sequence on ther-
modynamics.
Volume 2:Volume 2 begins with six chapters on electricity and magnetism, culminating
and concluding with a chapter on electromagnetic waves and relativity. Following this are
two chapters on optics one on geometrical optics and one on wave optics. The final four
chapters cover modern physics,including quanta,atoms,nuclei,and elementary particles.
Instructor Supplements
NOTE: For convenience, all of the following instructor supplements can also be down-
loaded from the Instructor Area, accessed via the left-hand navigation bar of Mastering-
PhysicsTM(www.masteringphysics.com).
The Instructor Solutions Manual,written by Brett Kraabel,Freddy Hansen,Michael
Schirber, Larry Stookey, Dirk Stueber, and Robert White, provides complete solutions to
all the end-of-chapter questions and problems. All solutions follow the Organize and
Plan/Solve/Reflect problem-solving strategy used in the textbook for quantitative prob-
lems and the Solve/Reflect strategy for qualitative ones. The solutions are available by
chapter in Word and PDF format and can be downloaded from the Instructor Resource
Center(www.pearsonhighered.com/educator).
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Preface to the Instructor ix
The cross-platform Instructor Resource DVD (ISBN 978-0-321-61126-0) provides
invaluable and easy-to-use resources for your class. The contents include a comprehensive
library of more than 220 applets from ActivPhysics OnLine ,as well as all figures,pho-
tos,tables,and summaries from the textbook in JPEG format. In addition,all the Problem-
Solving Strategies, Tactics Boxes, and Key Equations are provided in editable Word as
well as JPEG format. PowerPoint slides containing all the figures from the text are also
included,as well as Classroom Response Clicker questions.
MasteringPhysics (www.masteringphysics.com) is a homework,tutorial,and assess-
ment system designed to assign,assess,and track each students progress. In addition to the
textbooks end-of-chapter problems, MasteringPhysics for Essential College Physics also
includes prebuilt assignments and tutorials.
MasteringPhysics provides instructors with a fast and effective way to assign uncompro-
mising,wide-ranging online homework assignments of just the right difficulty and duration.
The tutorials coach 90% of students to the correct answer with specific wrong-answer
feedback. The powerful post-assignment diagnostics allow instructors to assess the progress
of their class as a whole or to quickly identify individual students areas of difficulty.
ActivPhysics OnLine (accessed through the Self Study area within www.mastering
physics.com) provides a comprehensive library of more than 420 tried and tested
ActivPhysicsapplets updated for web delivery using the latest online technologies. In addi-
tion, it provides a suite of highly regarded applet-based tutorials developed by education
pioneers Professors Alan Van Heuvelen and Paul D Alessandris. The ActivPhysicsmargin
icon directs students to specific exercises that complement the textbook discussion.
The online exercises are designed to encourage students to confront misconceptions,
reason qualitatively about physical processes,experiment quantitatively,and learn to think
critically. They cover all topics from mechanics to electricity and magnetism and from op-
tics to modern physics. The highly acclaimed ActivPhysics OnLinecompanion workbooks
help students work through complex concepts and understand them more clearly. More
than 220 applets from the ActivPhysics OnLinelibrary are also available on the Instructor
Resource DVD.
The Test Bankcontains more than 2000 high-quality problems,with a range of multiple-
choice,true/false, short-answer, and regular homework-type questions. Test files are pro-
vided in both TestGen® (an easy-to-use, fully networkable program for creating and
editing quizzes and exams) and Word format,and can be downloaded from www.pearson-
highered.com/educator.
Student Supplements
The Student Solutions Manuals Volume 1 (Chapters 1 14)(ISBN 978-0-321-61120-8)
and Volume 2 (Chapters 15 26) (ISBN 978-0-321-61128-4), written by Brett Kraabel,
Freddy Hansen,Michael Schirber,Larry Stookey,Dirk Stueber,and Robert White,provide
detailed solutions to half of the odd-numbered end-of-chapter problems. Following the
problem-solving strategy presented in the text,thorough solutions are provided to carefully
illustrate both the qualitative (Solve/Reflect) and quantitative (Organize and Plan/Solve/
Reflect) steps in the problem-solving process.
MasteringPhysics (www.masteringphysics.com) is a homework,tutorial,and assess-
ment system based on years of research into how students work physics problems and pre-
cisely where they need help. Studies show that students who use MasteringPhysics
significantly increase their final scores compared to those using handwritten homework.
MasteringPhysics achieves this improvement by providing students with instantaneous
feedback specific to their wrong answers,simpler sub-problems upon request when they get
stuck,and partial credit for their method(s) used. This individualized,24/7 Socratic tutoring
is recommended by nine out of ten students to their peers as the most effective and time-
efficient way to study.
Pearson eText is available through MasteringPhysics, either automatically when
MasteringPhysics is packaged with new books or as a purchased upgrade online. Allowing
students access to the text wherever they have access to the Internet,Pearson eText comprises
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x Preface to the Instructor
the full text,including figures that can be enlarged for better viewing. Within Pearson eText,
students are also able to pop up definitions and terms to help with vocabulary and the reading
of the material. Students can also take notes in Pearson eText,using the annotation feature at
the top of each page.
Pearson Tutor Services (www.pearsontutorservices.com) Each students subscription
to MasteringPhysics also contains complimentary access to Pearson Tutor Services,pow-
ered by Smarthinking, Inc. By logging in with their MasteringPhysics ID and password,
students will be connected to highly qualified e-instructors who provide additional,in-
teractive online tutoring on the major concepts of physics. Some restrictions apply; offer
subject to change.
ActivPhysics OnLine (accessed via www.masteringphysics.com) provides students
with a suite of highly regarded applet-based tutorials (see above). The following work-
books help students work though complex concepts and understand them more clearly.
The ActivPhysics margin icons throughout the book direct students to specific exercises
that complement the textbook discussion.
ActivPhysics OnLine Workbook Volume 1: Mechanics Thermal Physics
Oscillations & Waves (ISBN 978-0-805-39060-5)
ActivPhysics OnLine Workbook Volume 2:Electricity & Magnetism Optics Mod-
ern Physics(ISBN 978-0-805-39061-2)
Acknowledgments
A new full-year textbook in introductory physics doesn t just happen overnight or by acci-
dent. We begin by thanking the entire editorial and production staff at Pearson Education.
The idea for this textbook grew out of discussions with Pearson editors,particularly Adam
Black, whose initial encouragement and vision helped launch the project; and Nancy
Whilton,who helped hone and guide this text to its current essentials state. Other Pearson
staff who have rendered invaluable service to the project include Ben Roberts, Michael
Gillespie, Development Manager; Margot Otway, Senior Development Editor; Gabriele
Rennie,Development Editor; Mary Catherine Hagar,Development Editor; Martha Steele;
Senior Project Editor; and Claudia Trotch,Editorial Assistant. In the projects early days,
we were bolstered by many stimulating discussions with Jon Ogborn,whose introductory
textbooks have helped improve physics education in Great Britain. In addition to the
reviewers mentioned below,we are grateful to Charlie Hibbard,accuracy checker,for his
close scrutiny of every word,symbol,number,and figure; to Sen-Ben Liao for meticulous-
ly solving every question and problem and providing the answer list; and to Brett Kraabel,
Freddy Hansen,Michael Schirber,Larry Stookey,Dirk Stueber,and Robert White for the
difficult task of writing the Instructor Solutions Manual.We also want to thank production
supervisors Nancy Tabor and Shannon Tozier for their enthusiasm and hard work on the
project; Jared Sterzer and his colleagues at Pre-Press PMG for handling the composition of
the text; and Kristin Piljay,photo researcher.
Andrew Rex:I wish to thank my colleagues at the University of Puget Sound,whose sup-
port and stimulating collegiality I have enjoyed for almost 30 years. The universitys staff,
in particular Neva Topolski,has provided many hours of technical support throughout this
textbooks development. Thanks also to student staff member Dana Maijala for her techni-
cal assistance. I acknowledge all the students I have taught over the years,especially those
in College Physics classes. Seeing how they learn has helped me generate much of what
you see in this book. And last but foremost,I thank my wife Sharon for her continued sup-
port,encouragement,and amazing patience throughout the length of this project.
Richard Wolfson: First among those to be acknowledged for their contributions to this
project are the thousands of students in my introductory physics courses over three decades
at Middlebury College. Youve taught me how to convey physics ideas in many different
ways appropriate to your diverse learning styles, and your enthusiasm has convinced me
that physics really can appeal to a wide range of students for whom its not their primary
interest. Thanks also to my Middlebury faculty colleagues and to instructors around the