Ppt fransiska-fisikaunja2014

wavesmateri profil referensi

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Name : Fransiska R.Manik.STTL : Invaliden,24 mei 1996NIM : RSA1C314009Prodi : Pend.Fisika PGMIPA-U

MY PROFIL

WAVESWAVES

WAVESWAVES

Carries energy from one place to another Carries energy from one place to another Classified byClassified by what what they move through they move through

1.1. Mechanical WavesMechanical Wavesthe energy is transferred by vibrations of medium the energy is transferred by vibrations of medium (medium = matter)(medium = matter)ex/ ocean waves move through waterex/ ocean waves move through water

2.2. Electromagnetic waves (EM Waves)Electromagnetic waves (EM Waves)the energy moves through disturbances in the the energy moves through disturbances in the electromagnetic field.electromagnetic field.

a disturbance that transfers energy

WAVE STRUCTUREWAVE STRUCTURE

CREST (peak)AMPLITUDEresting to max peak

WAVELENGTH

TROUGH

MECHANICAL WAVESMECHANICAL WAVES

travel through & gradually lose energy to that medium

Examples:Examples: water, sound, rope, & water, sound, rope, &

spring wavesspring waves

Mechanical Media:Mechanical Media: water, air, rope, springwater, air, rope, spring

require a medium (the material through which the disturbance is moving) to transmit energy

Making a pulse

MECHANICAL WAVESMECHANICAL WAVESClassified by how medium vibrates

Pulse = direction of energy transfer

Vibration = direction of vibration of medium relative to pulse

3 types: Longitudinal, transverse, surface

MECHANICAL WAVESMECHANICAL WAVESClassified by how medium vibrates

Longitudinal Waves:Vibration is in the same direction as

wave pulse (parallel to wave pulse)

Transverse Waves:Vibration is at 900 (right angles) to wave pulse

Surface Waves:Vibration is circular Ex/ Ocean waves; surface waves

TRANVERSE WAVESTRANVERSE WAVES

Sideways or up & downSideways or up & down Examples:Examples:

S-type earthquake wavesS-type earthquake waves Electromagnetic (EM) or light Electromagnetic (EM) or light

waveswaves

Vibration is perpendicular to the direction of the motion of the wave

LONGITUDINAL WAVESLONGITUDINAL WAVES

Back and forth (compression & rarefraction)Back and forth (compression & rarefraction) Also called compression or pressure waveAlso called compression or pressure wave Examples:Examples:

P-type earthquake wavesP-type earthquake waves Sound wavesSound waves

Vibration is parallel to the direction of the motion of the wave

Rarefraction (expansion)

Compression

CHARACTERISTICS OF WAVESCHARACTERISTICS OF WAVESWaves are described according Waves are described according

to their to their AmplitudeAmplitude

measures DISPLACEMENTmeasures DISPLACEMENTsize of the disturbancesize of the disturbance

Wavelength Wavelength distance of a “repeating unit”distance of a “repeating unit”Also called a cycleAlso called a cycle

Velocity Velocity vv speed = how fast wave travelsspeed = how fast wave travels

AMPLITUDEAMPLITUDE

Distance between “rest & crest” or “rest & trough”Distance between “rest & crest” or “rest & trough”

Gives indication of “power” Gives indication of “power” or “strength” of waveor “strength” of wave(magnitude of earthquake = (magnitude of earthquake = Richter scale)Richter scale)

Does not affect Does not affect velocity of wavevelocity of wave

Determines loudness (sound) or brightness (EM wave)Determines loudness (sound) or brightness (EM wave)

WAVELENGTH WAVELENGTH Distance between any two Distance between any two

repeating points on a waverepeating points on a wave

crest-crest, crest-crest, trough-trough,trough-trough,expansion-expansion, expansion-expansion, compression-compressioncompression-compression

Determines what colorsDetermines what colorswe see; what notes we hear (pitch)we see; what notes we hear (pitch)

Shorter wavelengths have more Shorter wavelengths have more cycles per minute because they cycles per minute because they aren’t as longaren’t as long

VELOCITY VELOCITY vv the rate at which the the rate at which the

energy travelsenergy travels; ; speed & directionspeed & direction

Depends on mediumDepends on medium Mechanical waves travel Mechanical waves travel

faster through dense faster through dense mediumsmediums

EM Waves are faster EM Waves are faster through less dense through less dense mediumsmediums

Frequency Frequency ƒƒ

measured in measured in wavelengths/second or wavelengths/second or cycles/secondcycles/second

HertzHertz (Hz) = number of (Hz) = number of wavelengths in 1 secondwavelengths in 1 second

Frequency is related to Frequency is related to velocity:velocity: v v = = ƒ ƒ

How oftenHow often number of wavelengths that pass any point per secondnumber of wavelengths that pass any point per second

PERIOD TPERIOD T

How longHow longAmount of time for one wavelength to pass a pointAmount of time for one wavelength to pass a point

Related inversely to frequencyRelated inversely to frequency

11 == 11TT ff

PeriodPeriod == 11FrequencyFrequency

THANK YOUTHANK YOU

ReferensiReferensihttp://www.glenbrook.k12.il.us/gbssci/Phys/Class/waves/wavestoc.html

To test how well you understand go to http://www.physicsclassroom.com/Class/waves/u10l1c.cfm#emmech