Physics - Alyoops!

1 Physics FOR. DUMmIES.. by Steven Holzner Physics For Dummies . Published by Wiley Publishing, Inc. 111 River St. Hoboken, NJ 07030-5774. Copyright 2006 by Wiley Publishing, Inc., Indianapolis, Indiana Published by Wiley Publishing, Inc., Indianapolis, Indiana Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400, fax 978-646-8600. Requests to the Publisher for permission should be addressed to the Legal Department, Wiley Publishing, Inc.

2 , 10475 Crosspoint Blvd., Indianapolis, IN 46256, 317-572-3447, fax 317-572-4355, or online at http://. Trademarks: Wiley, the Wiley Publishing logo, For Dummies, the Dummies Man logo, A Reference for the Rest of Us!, The Dummies Way, Dummies Daily, The Fun and Easy Way, and related trade dress are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates in the United States and other countries, and may not be used without written permission. All other trademarks are the property of their respective owners. Wiley Publishing, Inc., is not associated with any product or vendor mentioned in this book. LIMIT OF LIABILITY/DISCLAIMER OF WARRANTY: THE PUBLISHER AND THE AUTHOR MAKE NO REP- RESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CON- TENTS OF THIS WORK AND SPECIFICALLY DISCLAIM ALL WARRANTIES, INCLUDING WITHOUT.

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4 CHANGED OR DISAPPEARED BETWEEN WHEN THIS WORK WAS WRITTEN AND WHEN IT IS READ. For general information on our other products and services, please contact our Customer Care Department within the at 800-762-2974, outside the at 317-572-3993, or fax 317-572-4002. For technical support, please visit Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. 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. 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.

5 Dr. Holzner received his 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. Publisher's Acknowledgments We're proud of this book; please send us your comments through our Dummies online registration form located at Some of the people who helped bring this book to market include the following: Acquisitions, Editorial, and Composition Services Media Development Project Coordinator: Maridee Ennis Project Editor: Natalie Faye Harris Layout and Graphics: Mary J. Gillot, Acquisitions Editor: Stacy Kennedy Denny Hager, Erin Zeltner Copy Editors: Josh Dials, Kristin DeMint Proofreaders: Laura Albert, Leeann Harney, Technical Editor: Joseph L.

6 Breeden Jessica Kramer, Arielle Mennelle, Joe Niesen, Carl William Pierce Editorial Manager: Michelle Hacker Indexer: Joan Griffitts Editorial Assistants: Hanna Scott, Nadine Bell, David Lutton Special Help Danielle Voirol Cover Photos: Getty Images/Photodisc Cartoons: Rich Tennant ( ). 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 Michael Spring, Vice President and Publisher, Travel Kelly Regan, Editorial Director, Travel Publishing for Technology Dummies Andy Cummings, Vice President and Publisher, Dummies Technology/General User Composition Services Gerry Fahey, Vice President of Production Services Debbie Stailey, Director of Composition Services Contents at a Glance Introduction.

7 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 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 Chapter 8: Getting Some Work out of Physics ..119. Chapter 9: Putting Objects in Motion: Momentum and Chapter 10: Winding Up with Angular Kinetics ..153. Chapter 11: Round and Round with Rotational Chapter 12: Springs-n-Things: Simple Harmonic Motion ..189. Part IV: Laying Down the Laws of Chapter 13: Turning Up the Heat with Thermodynamics.

8 207. Chapter 14: Here, Take My Coat: Heat Transfer in Solids and Chapter 15: When Heat and Work Collide: The Laws of Thermodynamics ..235. Part V: Getting a Charge out of Electricity and 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. Part VI: The Part of Tens ..339. Chapter 21: Ten Amazing Insights on Chapter 22: Ten Wild Physics Index ..361. Table of Contents About This Conventions Used in This Book ..2. What You're Not to Foolish Assumptions ..2. How This Book Is Part I: Putting Physics into Motion ..3. Part II: May the Forces of Physics Be with You ..3. Part III: Manifesting the Energy to Part IV: Laying Down the Laws of Thermodynamics.

9 3. Part V: Getting a Charge out of Electricity and Part VI: The Part of Tens ..4. Icons Used in This Where to Go from 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 Absorbing the Energy Around You ..9. Feeling Hot but Not Playing with Charges and Magnets ..10. Preparing for the Wild, Wild Physics Coming Chapter 2: Understanding Physics Fundamentals ..13. Don't Be Scared, It's Only Physics ..14. Measuring the World Around You and Making Don't mix and match: Keeping physical units From meters to inches and back again: Converting between Eliminating Some Zeros: Using Scientific Checking the Precision of Knowing which digits are significant ..21. Estimating Arming Yourself with Basic Algebra ..23. Tackling a Little Trig ..23. viii Physics For Dummies Chapter 3: Exploring the Need for Speed.

10 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 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.