With Modern Physics For Scientists and Engineers

Third Edition

Richard Wolfson Middlebury College

Jay M. Pasachoff Williams College

^ADDISON-WESLEY

An imprint of Addison Wesley Longman, Inc.

Reading, Massachusetts • Menlo Park, California • New York • Harlow, England Don Mills, Ontario • Sydney • Mexico City • Madrid • Amsterdam

Preface xiv

A Visual Guide t o the Book xix

The Authors xxiii

Color Key for Figures xxiv

Credits xxv

C h a p t e r 1 D o i n g Physics 1

1-1 Fields of Physics 2

1-2 The Simplicity of Physics 4

1-3 Measurement Systems 4

1-4 Changing Units 8

1-5 Dimensional Analysis 8

1-6 Scientific Notation 10

1-7 Accuracy and Significant Figures 12

1-8 Estimation 13

1-9 Analytic and Numerical Analysis 14

1-10 Problem Solving 15

Par t 1

Mechanics Chapter 2 Motion in a Straight Line

2-1 Average Motion

2-2 Instantaneous Velocity

2-3 Acceleration

2-4 Constant Acceleration

2-5 Using the Equations of Motion

2-6 The Constant Acceleration of Gravity

Chapter I The Vector Description of Motion

3-1 Vectors and Scalars

3-2 Vector Arithmetic

21 22

23

25

28

31

33

35

46

47

47

3-3 Coordinate Systems, Vector Components, and Unit Vectors 49

3-4 Velocity and Acceleration Vectors 53

3-5 Relative Motion 57

Chapter € Motion in More Than One Dimension 67

4-1 Velocity and Acceleration 68

4-2 Constant Acceleration 70

4-3 Projectile Motion 72

4-4 Uniform Circular Motion 79

4-5 Nonuniform Circular Motion 82

Force a n d M o t i o n 92

5-1 The Wrong Question 93

5-2 Newton's First and Second Laws 94

5-3 Forces 98

5-4 Applying Newton's Second Law 101

5-5 Mass and Weight: The Force of Gravity 104

5-6 Adding Forces 107

5-7 Newton's Third Law 109

5-8 Measuring Force 112

Chapter 6 Using Newton's Laws 122

6-1 Using Newton's Second Law 123

6-2 Multiple Objects 131

6-3 Circular Motion 135

6-4 Friction 139

6-5 Drag Forces 150

Chapter I Work, Energy, and Power 163

7-1 Work 164

7-2 Work and the Scalar Product 167

7-3 A Varying Force 168

Contents ix

7-4 Force and Work in Three Dimensions 172

7-5 Kinetic Energy 174

7-6 Power 176

Chapter 8 Conservation of Energy 187

8-1 Conservative and Nonconservative Forces 188

8-2 Potential Energy 190

8-3 Conservation of Mechanical Energy 194

8-4 Potential Energy Curves 197

8-5 Force and Potential Energy 199

8-6 Nonconservative Forces 201

8-7 Conservation of Energy and Mass-Energy 202

Chapter 9 Gravitation 213

9-1 Toward a Law of Gravity 214

9-2 Universal Gravitation 215

9-3 Orbital Motion 218

9-4 Gravitational Energy 223

9-5 The Gravitational Field 229

9-6 Tidal Forces 229

9-7 Gravity and the General Theory of Relativity 230

Chapter 10 Systems of Particles 238

10-1 Center of Mass 239

10-2 Momentum 246

10-3 Kinetic Energy in Many-Particle Systems 253

Chapter 11 Collisions 262

11-1 Impulse and Collisions 263

11-2 Collisions and the Conservation Laws 265

11-3 Inelastic Collisions 266

11-4 Elastic Collisions 268

Chapter 12 Rotational Motion 283

12-1 Angular Velocity and Acceleration 284

12-2 Torque 288

12-3 Rotational Inertia and the Analog

of Newton's Law 291

12-4 Rotational Energy 300

12-5 Rolling Motion 302

Rotational Vectors and Angular Momentum 313

13-1 Angular Velocity and Acceleration Vectors 314

13-2 Torque and the Vector Cross Product 315

13-3 Angular Momentum 318

13-4 Conservation of Angular Momentum 320

13-5 Rotational Dynamics in Three Dimensions 324

Chapter 14 Static Equilibrium 336

14-1 Conditions for Equilibrium 337

14-2 Center of Gravity 339

14-3 Examples of Static Equilibrium 341

14-4 Stability of Equilibria 346

Oscillations, Waves, and Fluids 361

Oscillatory Motion 362

15-1 Properties of Oscillatory Motion 363

15-2 Simple Harmonic Motion 364

15-3 Applications of Simple Harmonic Motion 370

15-4 Circular Motion and Simple Harmonic Motion: An Intimate Relation 376

15-5 Energy in Simple Harmonic Motion 378

15-6 Damped Harmonic Motion 380

15-7 Driven Oscillations and Resonance 382

Chapter 16 Wave Motion 391

16-1 Kinds of Waves 392

16-2 Wave Properties 393

16-3 Mathematical Description of Wave

Motion 395

16-4 Waves on a String 397

16-5 Wave Power and Intensity 399

16-6 The Superposition Principle and Wave Interference 403

16-7 The Wave Equation 407

x Contents

Chapter 17 Sound and Other Wave Phenomena 415

17-1 Sound Waves in Gases 416

17-2 The Speed of Sound in Gases 418

17-3 Sound Intensity 419

17-4 Sound Waves in Liquids and Solids 423

17-5 Wave Reflection and Refraction 424

17-6 Standing Waves 427

17-7 The Doppler Effect 431

17-8 Shockwaves 434

Chapter 18 Fluid Motion 441

18-1 Describing Fluids: Density and Pressure 442

18-2 Fluids at Rest: Hydrostatic Equilibrium 443

18-3 Archimedes' Principle and Buoyancy 448

18-4 Fluid Dynamics 451

18-5 Applications of Fluid Dynamics 456

18-6 Viscosity and Turbulence 460

Part 3

Thermodynamics 471

Chapter 19 Temperature and Heat 472

19-1 Macroscopic and Microscopic Descriptions 473

19-2 Temperature and Thermodynamic Equilibrium 473

19-3 Measuring Temperature 474

19-4 Temperature and Heat 477

19-5 Heat Capacity and Specific Heat 478

19-6 Heat Transfer 480

19-7 Thermal Energy Balance 486

Chapter 21 Heat, Work, and the First Law of Thermodynamics 517

21-1 The First Law of Thermodynamics 518

21-2 Thermodynamic Processes 520

21-3 Specific Heats of an Ideal Gas 532

Chapter 22 The Second Law of Thermodynamics 543

22-1 Reversibility and Irreversibility 544

22-2 The Second Law of Thermodynamics 544

22-3 Applications of the Second Law of

Thermodynamics 550

22-4 The Thermodynamic Temperature Scale 554

22-5 Entropy and the Quality of Energy 554

Par t 4

Electromagnetism 569

Chapter 23 Electric Charge, Force, and Field 570

23-1 Electromagnetism 571

23-2 Electric Charge 572

23-3 Coulomb's Law . 573

23-4 The Electric Field 578

23-5 Electric Fields of Charge Distributions 581

23-6 Matter in Electric Fields 587

Chapter 24 Gauss's Law 600

24-1 Electric Field Lines 601

24-2 Electric Flux 603

24-3 Gauss's Law 606

24-4 Using Gauss's Law 609

24-5 Fields of Arbitrary Charge Distributions 615

24-6 Gauss's Law and Conductors 617

Chapter 20 The Thermal Behavior of Matter 496

20-1 Gases 497

20-2 Phase Changes 503

20-3 Thermal Expansion 508

Chapter 2S Electric Potential

25-1 Potential Energy, Work, and the Electric Field

25-2 Potential Difference

25-3 Calculating Potential Difference

630

631

631

636

Contents xi

25-4 Potential Difference and the Electric Field

25-5 Potentials of Charged Conductors

Chapter 26 Electrostatic Energy and Capacitors

26-1 Energy of a Charge Distribution

26-2 Two Isolated Conductors

26-3 Energy and the Electric Field

26-4 Capacitors

26-5 Energy Storage in Capacitors

26-6 Connecting Capacitors

26-7 Capacitors and Dielectrics

Chapter 27 Electric Current

27-1 Electric Current

27-2 Conduction Mechanisms

27-3 Resistance and Ohm's Law

27-4 Electric Power

Chapter 28 Electric Circuits

28-1 Circuits and Symbols

28-2 Electromotive Force

28-3 Simple Circuits: Series and Parallel Resistors

28-4 Kirchhoff's Laws and Multiloop Circuits

28-5 Electrical Measuring Instruments

28-6 Circuits with Capacitors

28-7 Electrical Safety

Chapter 29 The Magnetic Field

29-1 What is Magnetism?

29-2 The Magnetic Force on a Moving Charge

29-3 The Motion of Charged Particles in Magnetic Fields

29-4 The Magnetic Force on a Current

29-5 A Current Loop in a Magnetic Field

Chapter 30 Sources of the Magnetic Field

30-1 The Biot-Savart Law

30-2 The Magnetic Force between Two Conductors

30-3 Ampere's Law

30-4 Using Ampere's Law

30-5 Solenoids and Toroids

30-6 Magnetic Matter

30-7 Magnetic Monopoles and Gauss's Law

643

646

658

659 Chapter 31 Electromagnetic Induction 660

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31-1 Induced Currents

31-2 Faraday's Law

31-3 Induction and the Conservation of Energy

31-4 Induced Electric Fields

31-5 Diamagnetism

Chapter 32 Inductance and Magnetic Energy

32-1 Mutual Inductance

32-2 Self-Inductance

32-3 Inductors in Circuits

32-4 Magnetic Energy

Chapter 33 Alternating-Current Circuits

33-1 Alternating Current

33-2 Circuit Elements in AC Circuits

33-3 LC Circuits

33-4 Driven RLC Circuits and Resonance

33-5 Power in AC Circuits

33-6 Transformers and Power Supplies

Chapter 34 Maxwell's Equations and Electromagnetic Waves

34-1 The Four Laws of Electromagnetism

34-2 Ambiguity in Ampere's Law

34-3 Maxwell's Equations

34-4 Electromagnetic Waves

34-5 The Speed of Electromagnetic Waves

34-6 Properties of Electromagnetic Waves

34-7 The Electromagnetic Spectrum

34-8 Polarization

34-9 Producing Electromagnetic Waves

34-10 Energy in Electromagnetic Waves

34-11 Wave Momentum and Radiation Pressure

778

780

785

788

793

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805

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819

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xi i Contents

vt 5

Optics

Chapter 35 Reflection and Refraction 35-1 Reflection and Transmission 35-2 Reflection 35-3 Refraction 35-4 Total Internal Reflection 35-5 Dispersion 35-6 Reflection and Polarization

Chapter 3S Image Formation and Optical Instruments

36-1 Plane Mirrors 36-2 Curved Mirrors 36-3 Lenses 36-4 Refraction in Lenses: The Details 36-5 Optical Instruments

Chapter 31 Interference and Diffraction

37-1 Coherence and Interference 37-2 Double-Slit Interference 37-3 Multiple-Slit Interference and Diffraction

Gratings 37-4 Thin Films and Interferometers 37-5 Huygens' Principle and Diffraction 37-6 Single-Slit Diffraction 37-7 The Diffraction Limit

915

916

917 918 919 924 927 929

938 939 941 948 952 958

971 972 974

978 983 989 990 995

Part 6 Modern Physics 1007

Chapter 38 Relativity 1008 38-1 Speed с Relative to What? 1009 38-2 Matter, Motion, and the Ether 1010 38-3 Special Relativity 1013 38-4 Space and Time in Relativity 1013 38-5 Energy and Momentum in Relativity 1029 38-6 What Is Not Relative 1033

38-7 Electromagnetism and Relativity 1035 38-8 General Relativity 1037

Chapter 3® Light and Matter: Waves or Particles? 1044

39-1 Toward the Quantum Theory 1045 39-2 Blackbody Radiation 1046 39-3 Photons 1050 39-4 Atomic Spectra and the Bohr Atom 1056 39-5 Matter Waves 1061 39-6 The Uncertainty Principle 1064 39-7 The Wave-Particle Duality,

Complementarity, and the Correspondence Principle 1068

Chapter 4© Quantum Mechanics 1074 40-1 Particles, Waves, and Probability 1075 40-2 The Schrödinger Equation 1077 40-3 The Infinite Square Well 1079 40-4 The Harmonic Oscillator 1084 40-5 Quantum Tunneling 1087 40-6 Finite Potential Wells 1091 40-7 Quantum Mechanics in Three

Dimensions 1092 40-8 Relativistic Quantum Mechanics 1093

Chapter 41 Atomic Physics 1100 41-1 The Hydrogen Atom 1101 41-2 Electron Spin 1108 41-3 The Pauli Exclusion Principle 1113 41-4 Multielectron Atoms and the

Periodic Table 1115 41-5 Transitions and Atomic Spectra 1120

Chapter 42 Molecular and Solid-State Physics 1133

42-1 Molecular Bonding 1134 42-2 Molecular Energy Levels 1138 42-3 Solids 1142 42-4 Superconductivity 1151

Chapter 43 Nuclear Physics 1161 43-1 Discovery of the Nucleus 1162

Contents xi i i

43-2 Binding Nuclei: Elements, Isotopes, and Stability 1163

43-3 Properties of the Nucleus 1165

43-4 Binding Energy 1170

43-5 Radioactivity 1173

43-6 Models of Nuclear Structure 1184

Chapter 4 4 Nuclear Energy: Fission and Fusion 1192

44-1 Energy from the Nucleus 1193

44-2 Nuclear Fission 1193

44-3 Applications of Nuclear Fission 1200

44-4 Nuclear Fusion 1209

Chapter 4S From Quarks to the Cosmos 1225

45-1 Particles and Forces 1226

45-2 Particles and More Particles 1227

45-3 Quarks and the Standard Model 1233

45-4 Unification

45-5 The Evolving Universe

Appendixes

1237

1242

Appendix. Ä Mathematics A-1

Append ix В The International

System of Units (SI) A-12

et td ix С Conversion Factors A-14

Appendix В The Elements A-17

Append i x E Astrophysical Data A-20

Got It! Answers A-21 Answers to Odd-Numbered Problems A-23 Index 1-1