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PHYSICS
DEMYSTIFIED
Other Titles in the McGraw-Hill Demystified Series
STAN GIBILISCO
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Astronomy Demystified
R
HONDA HUETTENMUELLER
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Algebra Demystified
S
TEVEN KRANTZ
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Calculus Demystified
PHYSICS
DEMYSTIFIED
STAN GIBILISCO
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DOI: 10.1036/0071412123
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DEDICATION
To Samuel, Tony, and Tim
from Uncle Stan
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CONTENTS
Preface xiii
Acknowledgments xv
PART ZERO A Review of Mathematics
CHAPTER 1 Equations, Formulas, and Vectors 3
Notation 3
One-Variable First-Order Equations 9
One-Variable Second-Order Equations 12
One-Variable Higher-Order Equations 18
Vector Arithmetic 20
Some Laws for Vectors 23
CHAPTER 2 Scientific Notation 29
Subscripts and Superscripts 29
Power-of-10 Notation 31
Rules for Use 35
Approximation, Error, and Precedence 40
Significant Figures 44
CHAPTER 3 Graphing Schemes 49
Rectangular Coordinates 49
The Polar Plane 62
Other Systems 64

CHAPTER 4 Basics of Geometry 77
Fundamental Rules 77
Triangles 86
Quadrilaterals 92
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CONTENTS
viii
Circles and Ellipses 101
Surface Area and Volume 103
CHAPTER 5 Logarithms, Exponentials,
and Trigonometry 113
Logarithms 113
Trigonometric Functions 124
Trigonometric Identities 127
Test: Part Zero 133
PART ONE Classical Physics
CHAPTER 6 Units and Constants 147
Systems of Units 147
Base Units in SI 148
Other Units 154
Prefix Multipliers 158
Constants 160
Unit Conversions 165
CHAPTER 7 Mass, Force, and Motion 171
Mass 171
Force 175
Displacement 176
Speed 178
Velocity 181

Acceleration 183
Newton’s Laws of Motion 188
CHAPTER 8 Momentum, Work, Energy, and Power 193
Momentum 193
Collisions 196
Work 202
Energy 204
Power 209
CHAPTER 9 Particles of Matter 217
Early Theories 217
The Nucleus 219
Outside the Nucleus 227
Energy from Matter 230
Compounds 234
CHAPTER 10 Basic States of Matter 241
The Solid Phase 242
The Liquid Phase 251
The Gaseous Phase 258
CHAPTER 11 Temperature, Pressure, and
Changes of State 265
What Is Heat? 265
Temperature 269
Some Effects of Temperature 275
Temperature and States of Matter 278
Test: Part One 285
PART TWO Electricity, Magnetism,
and Electronics
CHAPTER 12 Direct Current 297
What Does Electricity Do? 297
Electrical Diagrams 303

CONTENTS
ix
Voltage/Current/Resistance Circuits 305
How Resistances Combine 310
Kirchhoff’s Laws 318
CHAPTER 13 Alternating Current 323
Definition of Alternating Current 323
Waveforms 325
Fractions of a Cycle 329
Amplitude 332
Phase Angle 336
CHAPTER 14 Magnetism 345
Geomagnetism 345
Magnetic Force 347
Magnetic Field Strength 351
Electromagnets 354
Magnetic Materials 357
Magnetic Machines 361
Magnetic Data Storage 366
CHAPTER 15 More About Alternating Current 371
Inductance 371
Inductive Reactance 375
Capacitance 380
Capacitive Reactance 384
RLC Impedance 390
CHAPTER 16 Semiconductors 397
The Diode 397
The Bipolar Transistor 405
Current Amplification 410
The Field-Effect Transistor 412

Voltage Amplification 414
CONTENTS
x
CONTENTS
xi
The MOSFET 417
Integrated Circuits 421
Test: Part Two 425
PART THREE Waves, Particles,
Space, and Time
CHAPTER 17 Wave Phenomena 437
Intangible Waves 438
Fundamental Properties 440
Wave Interaction 448
Wave Mysteries 455
Particle or Wave? 459
CHAPTER 18 Forms of Radiation 467
EM Fields 467
ELF Fields 472
Rf Waves 474
Beyond the Radio Spectrum 481
Radioactivity 490
CHAPTER 19 Optics 499
Behavior of Light 499
Lenses and Mirrors 507
Refracting Telescopes 512
Reflecting Telescopes 515
Telescope Specifications 517
The Compound Microscope 521
CHAPTER 20 Relativity Theory 529

Simultaneity 529
Time Dilation 534
Spatial Distortion 539
Mass Distortion 541
General Relativity 544
Test: Part Three 557
Final Exam 567
Answers to Quiz, Test, and
Exam Questions 585
Suggested Additional References 593
Index 595
CONTENTS
xii
This book is for people who want to learn basic physics without taking a
formal course. It can also serve as a supplemental text in a classroom,
tutored, or home-schooling environment. I recommend that you start at the
beginning of this book and go straight through, with the possible exception
of Part Zero.
If you are confident about your math ability, you can skip Part Zero. But
take the Part Zero test anyway, to see if you are actually ready to jump into
Part One. If you get 90 percent of the answers correct, you’re ready. If you
get 75 to 90 percent correct, skim through the text of Part Zero and take
the chapter-ending quizzes. If you get less than three-quarters of the
answers correct in the quizzes and the section-ending test, find a good desk
and study Part Zero. It will be a drill, but it will get you “in shape” and
make the rest of the book easy.
In order to learn physics, you must have some mathematical skill. Math
is the language of physics. If I were to tell you otherwise, I’d be cheating
you. Don’t get intimidated. None of the math in this book goes beyond the
high school level.

This book contains an abundance of practice quiz, test, and exam questions.
They are all multiple choice, and are similar to the sorts of questions used
in standardized tests. There is a short quiz at the end of every chapter. The
quizzes are “open-book.” You may (and should) refer to the chapter texts
when taking them. When you think you’re ready, take the quiz, write down
your answers, and then give your list of answers to a friend. Have the
friend tell you your score, but not which questions you got wrong. The
answers are listed in the back of the book. Stick with a chapter until you
get most of the answers right.
This book is divided into three major sections after Part Zero. At the end
of each section is a multiple choice test. Take these tests when you’re done
with the respective sections and have taken all the chapter quizzes. The
section tests are “closed-book.” Don’t look back at the text when taking
them. The questions are not as difficult as those in the quizzes, and they
don’t require that you memorize trivial things. A satisfactory score is three-
quarters of the answers correct. Again, answers are in the back of the book.
PREFACE
Copyright 2002 by The McGraw-Hill Companies, Inc. Click here for Terms of Use.
PREFACE
xiv
There is a final exam at the end of this course. The questions are practical,
and are less mathematical than those in the quizzes. The final exam contains
questions drawn from Parts One, Two, and Three. Take this exam when you
have finished all the sections, all the section tests, and all of the chapter
quizzes. A satisfactory score is at least 75 percent correct answers.
With the section tests and the final exam, as with the quizzes, have a friend
tell you your score without letting you know which questions you missed.
That way, you will not subconsciously memorize the answers. You might
want to take each test, and the final exam, two or three times. When you
have gotten a score that makes you happy, you can check to see where your

knowledge is strong and where it is not so keen.
I recommend that you complete one chapter a week. An hour or two
daily ought to be enough time for this. Don’t rush yourself; give your mind
time to absorb the material. But don’t go too slowly either. Take it at a
steady pace and keep it up. That way, you’ll complete the course in a few
months. (As much as we all wish otherwise, there is no substitute for “good
study habits.”) When you’re done with the course, you can use this book,
with its comprehensive index, as a permanent reference.
Suggestions for future editions are welcome.
Stan Gibilisco
Illustrations in this book were generated with CorelDRAW. Some clip art
is courtesy of Corel Corporation, 1600 Carling Avenue, Ottawa, Ontario,
Canada K1Z 8R7.
I extend thanks to Mary Kaser, who helped with the technical editing of
the manuscript for this book.
ACKNOWLEDGMENTS
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Part Zero
A Review of
Mathematics
PART ZERO
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CHAPTER 1
Equations, Formulas,
and Vectors
An equation is a mathematical expression containing two parts, one on the
left-hand side of an equals sign (ϭ) and the other on the right-hand side. A
formula is an equation used for the purpose of deriving a certain value or
solving some practical problem. A vector is a special type of quantity in

which there are two components: magnitude and direction. Physics makes
use of equations, formulas, and vectors. Let’s jump in and immerse our-
selves in them. Why hesitate? You won’t drown in this stuff. All you need
is a little old-fashioned perseverance.
Notation
Equations and formulas can contain coefficients (specific numbers), con-
stants (specific quantities represented by letters of the alphabet), and/or vari-
ables (expressions that stand for numbers but are not specific). Any of the
common arithmetic operations can be used in an equation or formula. These
include addition, subtraction, multiplication, division, and raising to a power.
Sometimes functions are also used, such as logarithmic functions, exponen-
tial functions, trigonometric functions, or more sophisticated functions.
Addition is represented by the plus sign (ϩ). Subtraction is represented
by the minus sign (Ϫ). Multiplication of specific numbers is represented
CHAPTER 1
Copyright 2002 by The McGraw-Hill Companies, Inc. Click here for Terms of Use.
PART 0 A Review of Mathematics
4
either by a plus sign rotated 45 degrees (ϫ) or by enclosing the numerals
in parentheses and writing them one after another. Multiplication involving
a coefficient and one or more variables or constants is expressed by writing
the coefficient followed by the variables or constants with no symbols in
between. Division is represented by a forward slash (/) with the numerator
on the left and the denominator on the right. In complicated expressions, a
horizontal line is used to denote division, with the numerator on the top and
the denominator on the bottom. Exponentiation (raising to a power) is
expressed by writing the base value, followed by a superscript indicating
the power to which the base is to be raised. Here are some examples:
Two plus three 2 ϩ 3
Four minus seven 4 Ϫ 7

Two times five 2 ϫ 5 or (2)(5)
Two times x 2x
Two times (x ϩ 4) 2(x ϩ 4)
Two divided by x 2/x
Two divided by (x ϩ 4) 2/(x ϩ 4)
Three to the fourth power 3
4
x to the fourth power x
4
(x ϩ 3) to the fourth power (x ϩ 3)
4
SOME SIMPLE EQUATIONS
Here are some simple equations containing only numbers. Note that these
are true no matter what.
3 ϭ 3
3 ϩ 5 ϭ 4 ϩ 4
1,000,000 ϭ 10
6
Ϫ (Ϫ20) ϭ 20
Once in a while you’ll see equations containing more than one equals sign
and three or more parts. Examples are
3 ϩ 5 ϭ 4 ϩ 4 ϭ 10 Ϫ 2
1,000,000 ϭ 1,000 ϫ 1,000 ϭ 10
3
ϫ 10
3
ϭ 10
6
Ϫ(Ϫ20) ϭϪ1 ϫ (Ϫ20) ϭ 20
CHAPTER 1 Equations, Formulas, and Vectors

5
All the foregoing equations are obviously true; you can check them eas-
ily enough. Some equations, however, contain variables as well as num-
bers. These equations are true only when the variables have certain values;
sometimes such equations can never be true no matter what values the vari-
ables attain. Here are some equations that contain variables:
x ϩ 5 ϭ 8
x ϭ 2y ϩ 3
x ϩ y ϩ z ϭ 0
x
4
ϭ y
5
y ϭ 3x Ϫ 5
x
2
ϩ 2x ϩ 1 ϭ 0
Variables usually are represented by italicized lowercase letters from near
the end of the alphabet.
Constants can be mistaken for variables unless there is supporting text
indicating what the symbol stands for and specifying the units involved.
Letters from the first half of the alphabet often represent constants. A com-
mon example is c, which stands for the speed of light in free space (approx-
imately 299,792 if expressed in kilometers per second and 299,792,000 if
expressed in meters per second). Another example is e, the exponential
constant, whose value is approximately 2.71828.
SOME SIMPLE FORMULAS
In formulas, we almost always place the quantity to be determined all by
itself, as a variable, on the left-hand side of an equals sign and some
mathematical expression on the right-hand side. When denoting a for-

mula, it is important that every constant and variable be defined so that
the reader knows what the formula is used for and what all the quantities
represent.
One of the simplest and most well-known formulas is the formula for
finding the area of a rectangle (Fig. 1-1). Let b represent the length (in
meters) of the base of a rectangle, and let h represent the height (in meters)
measured perpendicular to the base. Then the area A (in square meters) of
the rectangle is
A ϭ bh
PART 0 A Review of Mathematics
6
A similar formula lets us calculate the area of a triangle (Fig. 1-2). Let b
represent the length (in meters) of the base of a triangle, and let h represent
the height (in meters) measured perpendicular to the base. Then the area A
(in square meters) of the triangle is
h
b
A
Fig. 1-1. A rectangle with base length b,
height h, and area A.
h
b
A
Fig. 1-2. A triangle with base length b,
height h, and area A.
A ϭ bh/2
Consider another formula involving distance traveled as a function of
time and speed. Suppose that a car travels at a constant speed s (in meters
per second) down a straight highway (Fig. 1-3). Let t be a specified length
of time (in seconds). Then the distance d (in meters) that the car travels in

that length of time is given by
CHAPTER 1 Equations, Formulas, and Vectors
7
d
ϭ
st
If you’re astute, you will notice something that all three of the preceding
formulas have in common: All the units “agree” with each other. Distances
are always given in meters, time is given in seconds, and speed is given in
meters per second. The preceding formulas for area will not work as shown
if A is expressed in square inches and d is expressed in feet. However, the
formulas can be converted so that they are valid for those units. This
involves the insertion of constants known as conversion factors.
CONVERSION FACTORS
Refer again to Fig. 1-1. Suppose that you want to know the area A in
square inches rather than in square meters. To derive this answer, you
must know how many square inches comprise one square meter. There
are about 1,550 square inches in one square meter. Thus we can restate
the formula for Fig. 1-1 as follows: Let b represent the length (in meters)
of the base of a rectangle, and let h represent the height (in meters) meas-
ured perpendicular to the base. Then the area A (in square inches) of the
rectangle is
A
ϭ
1,550bh
Look again at Fig. 1-2. Suppose that you want to know the area in square
inches when the base length and the height are expressed in feet. There are
exactly 144 square inches in one square foot, so we can restate the formula
for Fig. 1-2 this way: Let b represent the length (in feet) of the base of a tri-
angle, and let h represent the height (in feet) measured perpendicular to the

base. Then the area A (in square inches) of the triangle is
d
s
t
Fig. 1-3. A car traveling down a straight highway over distance d at
constant speed s for a length of time t.