Chapter 11 - Vibrations & Waves

Front 1

Oscillate

Back 1

Vibrate

Front 2

Periodic motion

Back 2

When each vibration takes the same amount of time

Front 3

Equilibrium position

Back 3

The spring's natural resting position (when it's not compressed or stretched)

Front 4

Hooke's Law

Back 4

F = -kx

Where F = restoring force; k = spring constant; x = displacement from equilibrium position

Front 5

Amplitude

Back 5

Maximum displacement from equilibrium position

Front 6

Cycle

Back 6

A complete compress and stretch "lap"

Front 7

Period

Back 7

T - Time for one oscillation (s)

Front 8

Frequency

Back 8

f - the number of complete cycles per second (Hz)

Front 9

Frequency formulas

Back 9

f = 1/T; T = 1/f;

Front 10

Simple Harmonic Motion (SHM)

Back 10

Any vibrating system for which the restoring force is directly proportional to the negative of the displacement (see Hooke's law)

Front 11

Simple Harmonic Oscillation (SHO)

Back 11

Any vibrating system for which the restoring force is directly proportional to the negative of the displacement (see Hooke's law)

Front 12

Total Energy of SHO

Back 12

E = 1/2 mv^2 + 1/2 kx

Front 13

Velocity in SHO

Back 13

V = +- V(max) sq(1-(x^2 / A^2))

Front 14

Period of SHM

Back 14

T = 2pi sq(m/k)

Front 15

Frequency of SHM

Back 15

f = 1/T = 1/2pi sq(k/m)

Front 16

Displacement as a function of time

Back 16

x = A cos ((2pi t) / T)

Front 17

Sinusoidal Motion

Back 17

The motion looks like sine (or cosine) function when graphed

Front 18

Restoring Force of Pendulum

Back 18

F = -mg sin (angle)

Front 19

Period for Simple Pendulum

Back 19

T = 2pi sq(L/g)

Front 20

Frequency for Simple Pendulum

Back 20

f = 1/2pi sq(g/L)

Front 21

Damped Harmonic Motion

Back 21

Dispruption in the Sinusoidal motion

Front 22

Underdamp

Back 22

Makes several swings before coming to rest;

Wiggly graph

Front 23

Overdamp

Back 23

The damping is so large it takes a long time to reach equilibrium position;

No wiggle;

Front 24

Critical Damp

Back 24

Equilibrium position is reached in the shortest amount of time;

Just the right amount og wiggle;

Front 25

Forced Vibration

Back 25

When a system with a particular frequency has an exernal force applied

Front 26

Natural Frequency

Back 26

The frequency at which a system tends to oscillate in the absence of any driving or damping external force

Front 27

Resonance

Back 27

When the external frequency is the same as the natural frequency

Front 28

Mechanical waves

Back 28

Requires a medium to travel in; Are local oscillations of matter;

Front 29

Waves

Back 29

Are moving oscillations that are not carrying matter

Front 30

Pulse

Back 30

1/2 oscillation

Front 31

Periodic Wave

Back 31

Continuous oscillations

Front 32

Wavelenght

Back 32

λ; The distance between two succesive identical points/crests;

Front 33

Crest

Back 33

Maximum amplitude

Front 34

Trough

Back 34

Minimum amplitude

Front 35

Wave velocity

Back 35

The velocity at which wave crests, or any other part of the wave, move

Front 36

Wave Velocity Formula (for Sinusoidal Waves)

Back 36

V = λf

Front 37

Speed of Wave on a Chord

Back 37

V = sq(Ft / (m/L))

Front 38

Tranverse Wave

Back 38

The wave direction and particle direction are perpendicular (like a hopprep)

Front 39

Longitudal Wave

Back 39

The wave direction and particle direction are the same (like a dragspel)

Front 40

Energy Transported by Waves

Back 40

The energy transported by wave is proportional to the square of the amplitude

Front 41

Intensity

Back 41

I = (E/t) / area = P / area

Front 42

Wave Front

Back 42

All the points along the wave forming the wave crest

Front 43

Ray

Back 43

A line drawn in the direction of wave motion; Perpendicular to wave front

Front 44

Law of Reflection

Back 44

The angle of reflection equals the angle of incidence

Front 45

The Angle of Incidence

Back 45

The angle the incident ray makes with the surface

Front 46

Interference

Back 46

Refers to what happens when two waves pass through the same region of space at the same time

Front 47

Principle of Superposition

Back 47

The algebraic sum of the waves' displacements

Front 48

Destructive Interference

Back 48

Two pulses have opposite displacement so they add up to zero

Front 49

Constructive Interference

Back 49

Two pulses add up to have a greater displacement

Front 50

Partly Destructive Interference

Back 50

When two pulses interactand don't grow larger but don't add up to zero

Front 51

Phase

Back 51

The relative position of two waves' crests

Front 52

Standing Waves!!

Back 52

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