Contents at a Glance
Introduction .................................................................1Part 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
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
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
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
Newton’s Grand Finale: The Third Law of Motion .....................................72
Tension shouldn’t cause stiff necks:
Friction in Newton’s third law.........................................................73
Analyzing angles and force in Newton’s third law ...........................75
Finding equilibrium ..............................................................................77
Chapter 6: What a Drag: Inclined Planes and Friction . . . . . . . . . . . . .81
Don’t Let It Get You Down: Dealing with Gravity .......................................81
Leaning Vertical: An Inclined Plane .............................................................82
Figuring out angles the easy way .......................................................83
Playing with acceleration ....................................................................84
Getting Sticky with Friction ..........................................................................85
Calculating friction and the normal force .........................................86
Conquering the coefficient of friction................................................86
Understanding static and kinetic friction..........................................87
Handling uphill friction........................................................................89
Determining How Gravity Affects Airborne Objects .................................94
Going up: Maximum height .................................................................94
Floating on air: Hang time ...................................................................95
Going down: Factoring the total time ................................................95
Firing an object at an angle .................................................................96
Chapter 7: Circling around Circular Motions and Orbits . . . . . . . . . . .99
Staying the Course: Uniform Circular Motion ..........................................100
Changing Direction: Centripetal Acceleration..........................................101
Controlling velocity with centripetal acceleration ........................101
Finding the magnitude of the centripetal acceleration .................102
Pulling Toward the Center: Centripetal Force ..........................................102
Negotiating Curves and Banks: Centripetal Force through Turns.........104
Getting Angular: Displacement, Velocity, and Acceleration ...................106
Dropping the Apple: Newton’s Law of Gravitation ..................................108
Deriving the force of gravity on the earth’s surface ......................109
Using the law of gravitation to examine circular orbits ................110
Looping the Loop: Vertical Circular Motion .............................................113
Part III: Manifesting the Energy to Work ....................117
Chapter 8: Getting Some Work out of Physics . . . . . . . . . . . . . . . . . . .119
Work: It Isn’t What You Think.....................................................................119
Working on measurement systems ..................................................120
Pushing your weight ..........................................................................120
Taking a drag.......................................................................................121
Considering Negative Work.........................................................................122
Getting the Payoff: Kinetic Energy .............................................................123
Breaking down the kinetic energy equation ...................................125
Putting the kinetic energy equation to use .....................................126
Calculating kinetic energy by using net force.................................127
Energy in the Bank: Potential Energy ........................................................128
Working against gravity .....................................................................129
Converting potential energy into kinetic energy............................130
Choose Your Path: Conservative versus Nonconservative Forces .......131
Up, Down, and All Around: The Conservation of Mechanical Energy......132
Determining final velocity with mechanical energy.......................134
Determining final height with mechanical energy..........................134
Powering Up: The Rate of Doing Work ......................................................135
Common units of power ....................................................................135
Alternate calculations of power .......................................................136
Chapter 9: Putting Objects in Motion: Momentum and Impulse . . . .137
Looking at the Impact of Impulse...............................................................137
Gathering Momentum..................................................................................139
The Impulse-Momentum Theorem: Relating Impulse and
Momentum ................................................................................................140
Shooting pool: Finding impulse and momentum............................141
Singing in the rain: An impulsive activity........................................142
When Objects Go Bonk: Conserving Momentum.....................................143
Measuring velocity with the conservation of momentum ............145
Measuring firing velocity with the conservation of momentum.....146
When Worlds (or Cars) Collide: Elastic and Inelastic Collisions ...........148
When objects bounce: Elastic collisions.........................................148
When objects don’t bounce: Inelastic collisions............................149
Colliding along a line..........................................................................149
Colliding in two dimensions..............................................................151
Chapter 10: Winding Up with Angular Kinetics . . . . . . . . . . . . . . . . . .153
Going from Linear to Rotational Motion ...................................................153
Understanding Tangential Motion .............................................................154
Finding tangential speed ...................................................................154
Finding tangential acceleration ........................................................156
Finding centripetal acceleration.......................................................156
Applying Vectors to Rotation .....................................................................158
Calculating angular velocity..............................................................158
Figuring angular acceleration ...........................................................159
Twisting and Shouting: Torque...................................................................160
Mapping out the torque equation ....................................................162
Understanding lever arms.................................................................162
Figuring out the torque generated ...................................................164
Recognizing that torque is a vector .................................................165
No Wobbling Allowed: Rotational Equilibrium.........................................166
Hanging a flag: A rotational equilibrium problem..........................167
Ladder safety: Introducing friction into rotational equilibrium......168
Chapter 11: Round and Round with Rotational Dynamics . . . . . . . . .173
Rolling Up Newton’s Second Law into Angular Motion...........................173
Converting tangential acceleration to angular acceleration ........175
Factoring in the moment of inertia ..................................................175
Examining Moments of Inertia....................................................................176
CD players and torque: An inertia example ....................................177
Angular acceleration and torque: Another inertia example .........179
Wrapping Your Head around Rotational Work and Kinetic Energy .......180
Doing some rotational work..............................................................180
Tracking down rotational kinetic energy ........................................182
Measuring rotational kinetic energy on a ramp .............................183
Can’t Stop This: Angular Momentum.........................................................185
Reviewing the conservation of angular momentum ......................186
Satellite orbits: A conservation
of angular momentum example ....................................................186
Chapter 12: Springs-n-Things: Simple Harmonic Motion . . . . . . . . .189
Hooking Up with Hooke’s Law....................................................................189
Keeping springs stretchy...................................................................190
Deducing that Hooke’s law is a restoring force ..............................191
Moving with Simple Harmonic Motion......................................................191
Examining basic horizontal and vertical simple
harmonic motion ............................................................................192
Diving deeper into simple harmonic motion ..................................193
Finding the angular frequency of a mass on a spring....................200
Factoring Energy into Simple Harmonic Motion ......................................202
Swinging with Pendulums ...........................................................................203
Part IV: Laying Down the Laws of Thermodynamics .....205
Chapter 13: Turning Up the Heat with Thermodynamics . . . . . . . . . .207
Getting into Hot Water.................................................................................208
When the thermometer says Fahrenheit.........................................208
When the thermometer says Celsius...............................................208
When the thermometer says Kelvin ................................................209
The Heat Is On: Linear Expansion..............................................................210
Deconstructing linear expansion .....................................................212
Workin’ on the railroad: A linear expansion example....................212
The Heat Continues On: Volume Expansion .............................................213
Going with the Flow (of Heat).....................................................................214
Changing Phases: When Temperatures Don’t Change ............................216
Breaking the ice with phase changes...............................................217
Understanding latent heat.................................................................218
Chapter 14: Here, Take My Coat: Heat Transfer
in Solids and Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .219
Boiling Water: Convection...........................................................................219
Too Hot to Handle: Conduction..................................................................220
Examining the properties that affect conduction
to find the conduction equation ...................................................221
Applying the heat-transferred-by-conduction equation................223
Emitting and Absorbing Light: Radiation..................................................224
You can’t see radiation, but it’s there..............................................225
Radiation and blackbodies................................................................226
Crunching Avogadro’s Number ..................................................................228
Forging the Ideal Gas Law ...........................................................................229
Gas pressure: An ideal gas law example..........................................231
Boyle’s Law and Charles’ Law: Alternative expressions
of the ideal gas law .........................................................................231
Tracking Ideal Gas Molecules.....................................................................232
Predicting air molecule speed ..........................................................232
Calculating kinetic energy in an ideal gas .......................................233
Chapter 15: When Heat and Work Collide:
The Laws of Thermodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .235
Gaining Thermal Equilibrium: The Zeroth Law of Thermodynamics ......235
Conserving Heat and Energy: The First Law of Thermodynamics ........236
Calculating conservation...................................................................237
Examining isobaric, isochoric, isothermal,
and adiabatic processes, oh my! ..................................................238
Figuring out specific heat capacities ...............................................245
When Heat Flows: The Second Law of Thermodynamics.......................246
Putting heat to work: Heat engines ..................................................246
Evaluating heat’s work: Heat engine efficiency ..............................247
Carnot says you can’t have it all ......................................................248
Going Cold: The Third (and Absolute Last) Law of Thermodynamics ....250
Part V: Getting a Charge out of Electricity
and Magnetism .........................................................251
Chapter 16: Zapping Away with Static Electricity . . . . . . . . . . . . . . .253
Plus and Minus: Electron and Proton Charges.........................................253
Push and Pull: Electric Forces ....................................................................254
Charging it to Coulomb’s law ............................................................255
Bringing objects together..................................................................255
Calculating the speed of electrons...................................................256
Looking at forces between multiple charges ..................................256
Influence at a Distance: Electric Fields......................................................258
Coming from all directions: Electric fields
from point charges .........................................................................259
Charging nice and steady: Electric fields
in parallel plate capacitors............................................................261
Electric Potential: Cranking Up the Voltage..............................................262
Calculating electric potential energy...............................................263
Realizing the potential in voltage .....................................................264
Discovering that electric potential is conserved ...........................265
Finding the electric potential of point charges ..............................266
Getting fully charged with capacitance ...........................................26
Chapter 17: Giving Electrons a Push with Circuits . . . . . . . . . . . . . . .271
Electrons on the March: Current................................................................271
Defining current..................................................................................272
Calculating the current in batteries .................................................272
Giving You Some Resistance: Ohm’s Law..................................................273
Determining current flow ..................................................................273
Examining resistivity..........................................................................274
Powering Up: Wattage..................................................................................275
Flowing from One to the Other: Series Circuits .......................................275
Splitting the Current: Parallel Circuits ......................................................276
Looping Together Electricity with Kirchoff’s Rules.................................278
Implementing the loop rule...............................................................279
Using multiple-loop circuits ..............................................................280
Conquering Capacitors in Parallel and Series Circuits ...........................283
Capacitors in parallel circuits...........................................................283
Capacitors in series circuits .............................................................284
Putting Together Resistors and Capacitors: RC Circuits ........................285
Chapter 18: Magnetism: More than Attraction . . . . . . . . . . . . . . . . . . .287
Finding the Source of Attraction ................................................................288
Forcing a Moving Charge.............................................................................289
Figuring the Quantitative Size of Magnetic Forces ..................................290
Moving in Orbits: Charged Particles in Magnetic Fields .........................292
Magnetic fields do no work . . . .........................................................292
. . . but they still affect moving charged particles..........................293
Pushing and Pulling Currents .....................................................................295
Forces on currents .............................................................................295
Torques on currents...........................................................................296
Identifying the Magnetic Field from a Wire...............................................298
Centering on Current Loops .......................................................................300
Achieving a Uniform Magnetic Field with Solenoids ...............................302
Chapter 19: Keeping the Current Going with Voltage . . . . . . . . . . . . .305
Inducing EMF (Electromagnetic Frequency) ............................................305
Moving a conductor in a magnetic field to cause voltage.............306
Inducing voltage over a certain area ...............................................307
Factoring In the Flux with Faraday’s Law..................................................308
Getting the Signs Right with Lenz’s Law ...................................................310
Figuring out Inductance ..............................................................................312
Examining Alternating Current Circuits ....................................................313
Picturing alternating voltage ............................................................314
Unearthing root mean square current and voltage........................314
Leading with capacitors ....................................................................315
Lagging with inductors ......................................................................318
Handling the Triple Threat: RCL Circuits..................................................321
Chapter 20: Shedding Some Light on Mirrors and Lenses . . . . . . . . .323
All about Mirrors (srorriM tuoba llA)........................................................323
When Light Gets Bendy...............................................................................324
Refracting light with Snell’s Law.......................................................324
Examining water at apparent depths...............................................325
All Mirrors and No Smoke ...........................................................................327
Expanding with concave mirrors .....................................................327
Contracting with convex mirrors .....................................................332
Seeing Clearly with Lenses..........................................................................333
Expanding with converging lenses...................................................334
Contracting with diverging lenses....................................................337
Part VI: The Part of Tens ............................................339
Chapter 21: Ten Amazing Insights on Relativity . . . . . . . . . . . . . . . . . .341
Nature Doesn’t Play Favorites ....................................................................341
The Speed of Light Is Constant, No Matter How Fast You Go ................342
Time Dilates at High Speeds .......................................................................343
Space Travel Ages You Less........................................................................343
Length Contracts at High Speeds...............................................................344
E = mc2: The Equivalence of Matter and Energy.......................................345
Matter Plus Antimatter Equals Boom........................................................345
The Sun Is Radiating Away Mass................................................................346
The Speed of Light Is the Ultimate Speed .................................................346
Newton Is Still Right.....................................................................................347
Chapter 22: Ten Wild Physics Theories . . . . . . . . . . . . . . . . . . . . . . . . .349
You Can Measure a Smallest Distance.......................................................349
There Might Be a Smallest Time.................................................................350
Heisenberg Says You Can’t Be Certain ......................................................350
Black Holes Don’t Let Light Out .................................................................351
Gravity Curves Space ..................................................................................351
Matter and Antimatter Destroy Each Other .............................................352
Supernovas Are the Most Powerful Explosions .......................................353
The Universe Starts with the Big Bang and Ends with the Gnab Gib ....353
Microwave Ovens Are Hot Physics............................................................353
Physicists May Not Have Physical Absolute Measures...........................354
Glossary ...................................................................355
Index........................................................................361
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