College Level Physics

Page 230

SUPERPOSITION AND INTERFERENCE Most waves are not simple waves. Most waves are complex because they are added together and subtracted from one another. This can be seen when looking at the waves on the ocean, which will have different heights at different times. Waves will superimpose upon themselves onto one another. This is referred to as superposition. The disturbances in these cases will be referred to as forces that will either add or subtract from one another. If two waves come together with the same peaks and same troughs, this will be called constructive interference. The wave will have twice the amplitude of individual waves but the wavelength will be the same. On the other hand, if two waves are identical and have the trough of one happen at the peak of another, this is referred to as destructive interference. Because the disturbances are in direct opposition to one another, the end result is a zero amplitude and no wavelength as the waves will cancel one another completely. In order for this to occur, the waves must be precisely identical and directly opposite to one another. This can happen to sound waves when stereo sound is used. Most wave additions and subtractions are not so simple. A large wave with a long wavelength and a small wave with a short wavelength will add together and will create an odd, complicated wave that has some periodicity that can be described. This will be a combination of constructive and destructive interference. Some waves will vibrate and will seem not to move directly. These types of waves can be seen in wave addition and subtraction of waves traveling in opposite directions. The resultant wave is described as a standing wave. Standing waves can be seen in organ pipes and with guitar strings; they look like quivering or vibration and will not appear to travel in any direction whatsoever. Nodes are the points where the string does not move and the wave disturbance is zero, while an antinode is the location of maximum wave amplitude. The frequency is related to the velocity of the wave. The lowest frequency of this type of wave addition and subtraction is called the fundamental frequency. This type of thing can be seen in sound waves, in which the

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Lens and Light Systems

2min
pages 314-316

Dispersion

1min
page 313

Mirror Images

2min
pages 317-318

Quiz

4min
pages 305-308

Refraction

4min
pages 310-312

Key Takeaways

0
page 304

Electromagnetic Waves

8min
pages 298-303

Inductance

1min
page 297

Electromagnetism

3min
pages 295-296

Magnetic Field and Currents

2min
pages 293-294

Meters

0
page 292

Motors

1min
page 291

Electromagnets

1min
page 285

Quiz

3min
pages 280-283

Electromotive Force

3min
pages 277-278

Key Takeaways

0
page 279

Alternating Current and Direct Current

1min
page 275

Electric Power and Energy

1min
page 274

Circuits

0
page 276

Electric Resistance and Resistivity

2min
pages 272-273

Ohm’s Law

1min
page 271

Quiz

4min
pages 264-267

Key Takeaways

0
page 263

Capacitors

6min
pages 258-262

Equipotential Lines

2min
pages 256-257

Quiz

3min
pages 249-252

Electrical Fields

6min
pages 242-247

Key Takeaways

0
page 248

Coulomb’s Law

0
page 241

Conductors and Insulators

3min
pages 239-240

Wave Energy

1min
pages 231-232

Quiz

4min
pages 234-237

Superposition and Interference

1min
page 230

Waves

2min
pages 228-229

Resonance

1min
page 227

Pendulums

1min
pages 224-225

Damped Harmonic Motion

0
page 226

Simple Harmonic Motion

2min
pages 220-223

Period and Frequency

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page 219

Key Takeaways

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page 212

Quiz

4min
pages 213-216

Heat Pumps

1min
page 208

Application of Thermodynamics

0
page 207

Second Law of Thermodynamics

3min
pages 200-202

The Four-Stroke Engine

4min
pages 203-206

Quiz

3min
pages 192-195

Radiation

2min
pages 189-190

Key Takeaway

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page 191

Convection

1min
page 188

Conduction

2min
pages 186-187

Heat Transfer Methods

1min
page 185

Key Takeaways

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page 175

Quiz

3min
pages 176-179

Evaporation and Boiling

1min
page 174

Thermal Expansion of Liquids and Solids

3min
pages 168-169

Phase Changes

1min
pages 172-173

Kinetic Theory

4min
pages 164-167

Quiz

4min
pages 159-162

Key Takeaways

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page 158

Diffusion through a Fluid

3min
pages 156-157

Bernoulli’s Equation

5min
pages 150-154

Fluid Flow

1min
page 149

Surface Tension

2min
pages 147-148

Archimedes Principle

2min
pages 145-146

Pascal’s Principle

2min
pages 143-144

Quiz

4min
pages 136-139

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page 135

Collisions of Rotating Objects

3min
pages 131-134

Angular Momentum

1min
page 130

Work of Rotation

3min
pages 128-129

Stable Equilibrium

1min
page 121

Rotational Motion

2min
pages 125-127

Angular Acceleration

1min
page 124

Simple Machines

1min
pages 122-123

Quiz

4min
pages 114-117

Key Takeaways

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page 113

Collisions in Two Dimensions

2min
pages 110-112

Inelastic Collisions in One Dimension

1min
page 109

Subatomic Collisions and Momentum Conservation

1min
page 107

Elastic Collisions in One Dimension

1min
page 108

Impulse

2min
pages 105-106

Quiz

4min
pages 100-103

Conservative and Nonconservative Forces

3min
pages 91-93

Gravity and Potential Energy

3min
pages 89-90

Quiz

4min
pages 82-85

Key Takeaways

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page 99

Newton’s Law of Gravitation

2min
pages 78-79

Nonconservative Forces

1min
page 94

Kepler’s Laws

1min
pages 80-81

Kinetic Energy

1min
page 88

The Coriolis Force

3min
pages 76-77

Centripetal Force

3min
pages 74-75

Centripetal Forces

1min
page 73

Quiz

4min
pages 67-70

Tension and Compression

1min
pages 64-65

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page 66

Elasticity, Stress, and Strain

1min
page 63

Friction

2min
pages 61-62

Tension

3min
pages 57-58

Forces in Physics

2min
pages 55-56

Newtonian Forces

1min
page 60

Quiz

4min
pages 47-50

Applications of Newton’s Laws

1min
page 59

Newton’s Third Law

2min
page 54

Key Takeaways

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page 46

Vector Addition and Subtraction via Graphical Methods

2min
pages 33-34

Preface

9min
pages 12-16

Velocity in Two Dimensions

3min
pages 43-45

Projectile Motion

3min
pages 39-41

Quiz

2min
pages 27-30

Range of a Projectile

2min
page 42

Velocity and Acceleration

6min
pages 20-23

Falling Objects

2min
pages 24-25
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