Physics for dummies

387 Pages·1975·6.09 MB·English

by  Steven Holzner

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Physics
FOR
DUMmIES
‰
by Steven Holzner

01_554336 ffirs.qxd 11/2/05 11:25 PM Page i
Physics
FOR
DUMmIES
‰
by Steven Holzner
01_554336 ffirs.qxd 11/2/05 11:25 PM Page ii
Physics For Dummies®
Published by
Wiley Publishing, Inc.
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Hoboken, NJ 07030-5774
www.wiley.com
Copyright © 2006 by Wiley Publishing, Inc., Indianapolis, Indiana
Published by Wiley Publishing, Inc., Indianapolis, Indiana
Published simultaneously in Canada
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Library of Congress Control Number: 2005933603
ISBN-13: 978-0-7645-5433-9
ISBN-10: 0-7645-5433-6
Manufactured in the United States of America
10 9 8 7 6 5 4 3 2 1
1B/RY/RR/QV/IN
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About the Author
Steven Holzner is an award-winning author of 94 books that have sold over
two million copies and been translated into 18 languages. He served on the
Physics faculty at Cornell University for more than a decade, teaching both
Physics 101 and Physics 102. Dr. Holzner received his Ph.D. in physics from
Cornell and performed his undergrad work at MIT, where he has also served
as a faculty member.
Dedication
To Nancy.
Author’s Acknowledgments
Any book such as this one is the work of many people besides the author. I’d
like to thank my acquisitions editor, Stacy Kennedy, and everyone else who
had a hand in the book’s contents, including Natalie Harris, Josh Dials, Joe
Breeden, et al. Thank you, everyone.
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Publisher’s Acknowledgments
We’re proud of this book; please send us your comments through our Dummies online registration
form located at www.dummies.com/register/.
Some of the people who helped bring this book to market include the following:
Acquisitions, Editorial, and Composition Services
MediaDevelopment
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Project Editor: Natalie Faye Harris
Layout and Graphics: Mary J. Gillot,
Acquisitions Editor: Stacy Kennedy Denny Hager, ErinZeltner
Copy Editors: Josh Dials, Kristin DeMint Proofreaders: Laura Albert, Leeann Harney,
Jessica Kramer, Arielle Mennelle,
Technical Editor: Joseph L. Breeden
JoeNiesen, Carl William Pierce
Editorial Manager: Michelle Hacker
Indexer: Joan Griffitts
Editorial Assistants: Hanna Scott, Nadine Bell,
Special Help
David Lutton
Danielle Voirol
Cover Photos: © Getty Images/Photodisc
Cartoons: Rich Tennant (www.the5thwave.com)
Publishing and Editorial for Consumer Dummies
Diane Graves Steele, Vice President and Publisher, Consumer Dummies
Joyce Pepple, Acquisitions Director, Consumer Dummies
Kristin A. Cocks, Product Development Director, Consumer Dummies
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Kelly Regan,Editorial Director, Travel
Publishing for Technology Dummies
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Composition Services
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Debbie Stailey,Director of Composition Services
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Contents at a Glance
Introduction.................................................................1
Part I: Putting Physics into Motion................................5
Chapter 1: Using Physics to Understand Your World....................................................7
Chapter 2: Understanding Physics Fundamentals.......................................................13
Chapter 3: Exploring the Need for Speed......................................................................25
Chapter 4: Following Directions: Which Way Are You Going?....................................43
Part II: May the Forces of Physics Be with You.............61
Chapter 5: When Push Comes to Shove: Force............................................................63
Chapter 6: What a Drag: Inclined Planes and Friction.................................................81
Chapter 7: Circling around Circular Motions and Orbits............................................99
Part III: Manifesting the Energy to Work....................117
Chapter 8: Getting Some Work out of Physics............................................................119
Chapter 9: Putting Objects in Motion: Momentum and Impulse..............................137
Chapter 10: Winding Up with Angular Kinetics..........................................................153
Chapter 11: Round and Round with Rotational Dynamics........................................173
Chapter 12: Springs-n-Things: Simple Harmonic Motion..........................................189
Part IV: Laying Down the Laws of Thermodynamics.....205
Chapter 13: Turning Up the Heat with Thermodynamics.........................................207
Chapter 14: Here, Take My Coat: Heat Transfer in Solids and Gases.......................219
Chapter 15: When Heat and Work Collide: The Laws of Thermodynamics............235
Part V: Getting a Charge out of Electricity
and Magnetism.........................................................251
Chapter 16: Zapping Away with Static Electricity......................................................253
Chapter 17: Giving Electrons a Push with Circuits....................................................271
Chapter 18: Magnetism: More than Attraction...........................................................287
Chapter 19: Keeping the Current Going with Voltage................................................305
Chapter 20: Shedding Some Light on Mirrors and Lenses........................................323
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Part VI: The Part of Tens...........................................339
Chapter 21: Ten Amazing Insights on Relativity.........................................................341
Chapter 22: Ten Wild Physics Theories.......................................................................349
Glossary...................................................................355
Index.......................................................................361
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Table of Contents
Introduction..................................................................1
About This Book...............................................................................................1
Conventions Used in This Book.....................................................................2
What You’re Not to Read.................................................................................2
Foolish Assumptions.......................................................................................2
How This Book Is Organized...........................................................................2
Part I: Putting Physics into Motion......................................................3
Part II: May the Forces of Physics Be with You..................................3
Part III: Manifesting the Energy to Work..............................................3
Part IV: Laying Down the Laws of Thermodynamics.........................3
Part V: Getting a Charge out of Electricity and Magnetism...............3
Part VI: The Part of Tens.......................................................................4
Icons Used in This Book..................................................................................4
Where to Go from Here....................................................................................4
Part I: Putting Physics into Motion.................................5
Chapter 1: Using Physics to Understand Your World . . . . . . . . . . . . . . .7
What Physics Is All About...............................................................................7
Observing Objects in Motion..........................................................................8
Absorbing the Energy Around You................................................................9
Feeling Hot but Not Bothered.......................................................................10
Playing with Charges and Magnets..............................................................10
Preparing for the Wild, Wild Physics Coming Up.......................................11
Chapter 2: Understanding Physics Fundamentals . . . . . . . . . . . . . . . . .13
Don’t Be Scared, It’s Only Physics...............................................................14
Measuring the World Around You and Making Predictions......................15
Don’t mix and match: Keeping physical units straight....................16
From meters to inches and back again:
Converting between units................................................................17
Eliminating Some Zeros: Using Scientific Notation....................................20
Checking the Precision of Measurements...................................................21
Knowing which digits are significant.................................................21
Estimating accuracy.............................................................................22
Arming Yourself with Basic Algebra............................................................23
Tackling a Little Trig......................................................................................23
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Physics For Dummies
Chapter 3: Exploring the Need for Speed . . . . . . . . . . . . . . . . . . . . . . . .25
Dissecting Displacement...............................................................................26
Examining axes.....................................................................................27
Measuring speed..................................................................................28
Speed Specifics: What Is Speed, Anyway?...................................................29
Reading the speedometer: Instantaneous speed.............................30
Staying steady: Uniform speed...........................................................30
Swerving back and forth: Nonuniform motion.................................30
Busting out the stopwatch: Average speed......................................31
Pitting average speed versus uniform motion..................................31
Speeding Up (or Down): Acceleration.........................................................33
Defining acceleration...........................................................................33
Determining the units of acceleration...............................................33
Positive and negative acceleration....................................................35
Average and instantaneous acceleration..........................................36
Uniform and nonuniform acceleration..............................................37
Relating Acceleration, Time, and Displacement........................................37
Not-so-distant relations.......................................................................38
Equating more speedy scenarios.......................................................39
Linking Speed, Acceleration, and Displacement........................................40
Chapter 4: Following Directions: Which Way Are You Going? . . . . . .43
Conquering Vectors.......................................................................................43
Asking for directions: Vector basics..................................................44
Putting directions together: Adding vectors....................................45
Taking distance apart: Subtracting vectors......................................46
Waxing Numerical on Vectors.......................................................................47
Breaking Up Vectors into Components.......................................................49
Finding vector components given magnitudes and angles.............49
Finding magnitudes and angles given vector components.............51
Unmasking the Identities of Vectors............................................................53
Displacement is a vector.....................................................................54
Velocity is another vector...................................................................54
Acceleration: Yep, another vector......................................................55
Sliding Along on Gravity’s Rainbow: A Velocity Exercise..........................57
Part II: May the Forces of Physics Be with You .............61
Chapter 5: When Push Comes to Shove: Force . . . . . . . . . . . . . . . . . . .63
Forcing the Issue............................................................................................63
For His First Trick, Newton’s First Law of Motion.....................................64
Getting it going: Inertia and mass......................................................65
Measuring mass....................................................................................65
Ladies and Gentlemen, Newton’s Second Law of Motion.........................66
Naming units of force...........................................................................67
Gathering net forces.............................................................................67