Back-of-the-envelope physics / Clifford Swartz.

Format:

Book

Author/Creator:

Swartz, Clifford E.

Language:

English

Subjects (All):

Physics--Miscellanea.

Physics.

Genre:

Trivia and miscellanea.

Physical Description:

xvii, 155 pages : illustrations ; 22 cm

Place of Publication:

Baltimore : Johns Hopkins University Press, 2003.

Summary:

Physicists use back-of-the-envelope estimates to check whether or not an idea could possibly be right. In many cases, the approximate solution is all that is needed. This compilation of 101 examples of back-of-the-envelope calculations celebrates a quantitative approach to solving physics problems. Drawing on a lifetime of physics research and nearly three decades as the editor of The Physics Teacher, Clifford Swartz provides simple, approximate solutions to physics problems that span a broad range of topics. What note do you get when you blow across the top of a Coke bottle? Could you lose weight on a diet of ice cubes? How can a fakir lie on a bed of nails without getting hurt? Does draining water in the northern hemisphere really swirl in a different direction than its counterpart below the equator? In each case, only a few lines of arithmetic and a few natural constants solve a problem to within a few percent. Covering such subjects as astronomy, magnetism, optics, sound, heat, mechanics, waves, and electricity, the book provides a rich source of material for teachers and anyone interested in the physics of everyday life. If the physical world is to make sense to students (o

Contents:

Chapter 1 Force and Pressure 1

Bed of Nails 1

Simple Thumbtack 2

Horsepower 2

Buoyancy in Air 3

How Dense Is the Ocean? 4

Washbowls and Coriolis Force 5

Points of Contact 6

Atmospheric Force 7

Weighing Your Car 8

Well and Water Tower 9

Pressure of Sunlight 10

Squashed Tennis Ball 11

Recoil 13

Fatal Impulse 14

Relative Gravitational Weakness 16

Strong Fields 17

Airplane Lift 19

Chapter 2 Mechanics and Rotation 22

Terminal Velocity 22

The Unlikely Game of Baseball 24

Human Levers 25

Angular Momenta 27

The Twirling Skater 28

Rotating Water Pail 30

Grandfather Clock 31

Arm and Leg Pendulums 32

Precession of a Bicycle Wheel 34

Car Springs 35

Carousels and Rotors 36

Banked Road 37

Conical Pendulum 39

Chapter 3 Sound and Waves 41

Speed of Sound 41

Tsunamis and Ripples 43

Cold Flat Music 46

Thunder and Lightning 47

Wavelengths of Familiar Sounds 47

Scales and Chords 50

The Sound of Coke 52

The Sensitive Ear 54

[lambda] of Visible Light 55

[lambda]v = c; hv = E 56

Trains and Doppler Shift 58

Chapter 4 Heat 60

Human Heaters 60

Negative Calorie Diet 60

The Moral of the Tail 61

Ice Skating 64

Thermal Expansion 66

Power Plant Efficiency 68

Chapter 5 Optics 71

Microscope Constraints 71

Binocular Size and Power 72

Seeing under Water 74

Candle Power 75

Chapter 6 Electricity 77

Electrostatic Charge on a Balloon 77

Capacitors 78

Capacitance of Spheres 80

Electric Field in a Wire 81

Electron Drift Speed 82

Unfamiliar Currents 84

High Cost of Battery Electricity 86

Magnet Strength 86

Matching Earth's B Field 87

Hanging Wire 89

Energy Storage in L and C 90

Jump-Rope Generator 92

Q of a Crystal Radio 93

E and B from a Lightbulb 95

Toaster Power 96

Magnetic Resonance Imaging 97

Chapter 7 Earth 100

Radius of Earth 100

Geography and Weight 101

g(R) 102

Height of Atmosphere 104

Depth of Earth's Gravity Field 105

Mountain Height 106

Earth Orbits 108

Escape Energy from Earth 109

Precession of the Equinoxes 109

Hole through the Earth 112

Slowing of the Earth's Rotation 113

Mass of Earth's Gravitational Field 116

Chapter 8 Astronomy 118

Diameter of Sun and Moon 118

Minimum Distance to Nearest Star 119

Pressure of Sunlight 120

How Many Photons to See a Faint Star? 121

Fueling the Sun 122

Age of the Elements 124

The 21cm Line 125

The Prodigal Sun 126

Chapter 9 Atoms and Molecules 128

All Atoms Are (about) the Same Size 128

Density of Air 130

Molecular Spacing in a Gas 131

Molar Energy 131

Latent Heat of Fusion and Vaporization 132

Surface Tension 134

Binding Force between Atoms 134

Atomic Spring Constant 139

Chapter 10 Particles and Quanta 141

Uncertainties of Photons and Mesons 141

Valence Electrons 142

Can Electrons Reside in the Nucleus? 144

Lucky Millikan 145

Nuclear Repulsion 148

Cyclotron 150

Synchrotron

Loss and Gain 151

Quantized Molecular Levels 153

Molecular Rotation Energy 155.

ISBN:

0801872634

OCLC:

50476732