WAVESWAVES
SIMPLE HARMONIC SIMPLE HARMONIC MOTIONMOTIONPROPERTIES OF WAVESPROPERTIES OF WAVESWAVE INTERFERENCEWAVE INTERFERENCESOUND WAVESSOUND WAVES
Telephone TEST - 50 Telephone TEST - 50 points points Write your set of 5 words for transmission .Write your set of 5 words for transmission .
Write words you heard in 1 minute .Write words you heard in 1 minute .Take turns . Take turns . Repeat for a different phone .Repeat for a different phone .Describe the clarity of transmission of data Describe the clarity of transmission of data Using :Using :a.a. String PhoneString Phoneb.b. Shorter String PhoneShorter String Phonec.c. Fishing line PhoneFishing line Phoned.d. Shorter Fishing line PhoneShorter Fishing line Phonee.e. Wire Phone Wire Phone f.f. Shorter Wire Phone Shorter Wire Phone LABORATORY REPORT – 50 POINTS LABORATORY REPORT – 50 POINTS Purpose :Purpose :Determine the best medium( string. Fishing line, wire) to transmit Determine the best medium( string. Fishing line, wire) to transmit
sound waves .Why ? sound waves .Why ? What is the effect of the length of the medium to sound wave What is the effect of the length of the medium to sound wave
transmission .transmission .Materials :Materials :Data Table Data Table Conclusion :Conclusion :
Pendulum Motion Packet Pendulum Motion Packet
Groups of 4 Groups of 4 a.a. Force Analysis Of PendulumForce Analysis Of Pendulumb.b. Sinusoidal Nature of a PendulumSinusoidal Nature of a Pendulumc.c. Energy analysis Energy analysis d.d. Period of A Pendulum Period of A Pendulum Read your topic – 20 minutesRead your topic – 20 minutesTake Notes Take Notes Share your information – 5minutes /each Share your information – 5minutes /each
person .person .Write and number all the information about Write and number all the information about
pendulum regarding all subtopic on paper pendulum regarding all subtopic on paper . Score it. . Score it.
Spring Motion Packet Spring Motion Packet
Groups of 4 Groups of 4 a.a. Force Analysis Of SpringForce Analysis Of Springb.b. Sinusoidal Nature of a SpringSinusoidal Nature of a Springc.c. Energy analysis Energy analysis d.d. Period of A SpringPeriod of A SpringRead your topic – 20 minutesRead your topic – 20 minutesTake Notes Take Notes Share your information – 5minutes /each Share your information – 5minutes /each
person .person .Write and number all the information about Write and number all the information about
pendulum regarding all subtopic on paper pendulum regarding all subtopic on paper . Score it. . Score it.
SIMPLE HARMONIC SIMPLE HARMONIC MOTIONMOTION
Motion that is repeating or periodic.Motion that is repeating or periodic. Two typesTwo types SpringSpring
Hooke’s Law states that the restoring Hooke’s Law states that the restoring force is proportional to the displacementforce is proportional to the displacement
F = -kxF = -kx Units: NewtonsUnits: Newtons Negative: direction of the Force is Negative: direction of the Force is
opposite the displacement.opposite the displacement.
SIMPLE HARMONIC SIMPLE HARMONIC MOTIONMOTION
Stretch or compression provides three types of Stretch or compression provides three types of energy.energy.
Max displacementMax displacement EPE = EPE = ½ k x ½ k x 22
V = 0V = 0 A increase to maxA increase to max
Equilibrium positionEquilibrium position Min xMin x Max KEMax KE Max velocityMax velocity a = 0a = 0
SIMPLE HARMONIC SIMPLE HARMONIC MOTIONMOTION
Horizontal springs: Horizontal springs: EPE EPE elasticelastic KEKE
Vertical springs: Vertical springs: PE PE gravitationalgravitational
EPE EPE elasticelastic KEKE
Conservation of energy appliesConservation of energy applies Friction or damping forceFriction or damping force
SIMPLE HARMONIC SIMPLE HARMONIC MOTIONMOTION
Period of a springPeriod of a spring T = 2T = 2 √ m/k√ m/k Units: sec/cycle or sec/revolution or secUnits: sec/cycle or sec/revolution or sec f = 1 / Tf = 1 / T Units: cycle/sec or revolution/sec or Hertz or sUnits: cycle/sec or revolution/sec or Hertz or s -1-1
SIMPLE HARMONIC SIMPLE HARMONIC MOTIONMOTION
Simple pendulumSimple pendulum For small anglesFor small angles Restoring force is proportional to x.Restoring force is proportional to x. Work done is ZEROWork done is ZERO Max PE at the highest pointMax PE at the highest point Max KE at the lowest pointMax KE at the lowest point Period of a pendulumPeriod of a pendulum T = 2T = 2 √ l/g√ l/g Units: sec/cycle or sec/revolution or secUnits: sec/cycle or sec/revolution or sec
PROPERTIES OF WAVESPROPERTIES OF WAVES
Follows a simple harmonic motionFollows a simple harmonic motion Needs a sourceNeeds a source Medium = matterMedium = matter Matter does NOT travel only energyMatter does NOT travel only energy Mechanical waves need a medium to travelMechanical waves need a medium to travel EM does not need a medium to travelEM does not need a medium to travel Pulse: single wavePulse: single wave
PROPERTIES OF WAVESPROPERTIES OF WAVES
Two types of wavesTwo types of wavesTransverse wavesTransverse waves
Disturbance is perpendicular to the Disturbance is perpendicular to the propagationpropagation
EMEM
PROPERTIES OF WAVESPROPERTIES OF WAVES
Longitudinal or compressional Longitudinal or compressional waveswavesDisturbance is parallel to the Disturbance is parallel to the
propagationpropagationSound wavesSound waves
PROPERTIES OF WAVESPROPERTIES OF WAVES
Parts of the waveParts of the wave Wavelength (Wavelength (): length of a wave ): length of a wave
measured between two consecutive measured between two consecutive identical pointsidentical points
Frequency (f)Frequency (f) Period (T)Period (T) Amplitude (A): max height of the waveAmplitude (A): max height of the wave
PROPERTIES OF WAVESPROPERTIES OF WAVES
Crest: highest point of transverse waveCrest: highest point of transverse wave Trough: lowest point of transverse waveTrough: lowest point of transverse wave
PROPERTIES OF WAVESPROPERTIES OF WAVES
Compression: high density portion of Compression: high density portion of compressional wavecompressional wave
Rarefaction: low density portion of Rarefaction: low density portion of compressional wavecompressional wave
HWK pg 396HWK pg 3961) repeating motion through 1) repeating motion through
equilibrium position…F is equilibrium position…F is proportional to xproportional to x
2) varies2) varies3) no, a changes…zero at 3) no, a changes…zero at
equilibrium position and equilibrium position and greatest at max greatest at max displacementdisplacement
4) No for angles less than 15 4) No for angles less than 15 degreesdegrees
5) GPE…GPE to KE to GPE5) GPE…GPE to KE to GPE6) frictional forces are 6) frictional forces are
neglectedneglected7) tangent component; pulls 7) tangent component; pulls
the bob toward the the bob toward the equilibrium positionequilibrium position
8) 130 N/m8) 130 N/m
9) 580 N/m9) 580 N/m
10) 2 x10) 2 x
11) 4 A11) 4 A
12) Inversely related12) Inversely related
13) Square root of 2; 13) Square root of 2; independent of massindependent of mass
14) same; independent of 14) same; independent of massmass
15) no; g changes so T 15) no; g changes so T changeschanges
16) Make shorter16) Make shorter
17) Increase; g decreases17) Increase; g decreases
18) Same; independent of a18) Same; independent of a
HWKHWK19) 9.7 m19) 9.7 m20) a) 2.000 s20) a) 2.000 s b) 9.812 m/s/sb) 9.812 m/s/s c) 9.798 m/s/sc) 9.798 m/s/s21) a) 0.57 s21) a) 0.57 s b) 1.8 Hzb) 1.8 Hz22) Movement of disturbance22) Movement of disturbance23) transverse: disturbance 23) transverse: disturbance
is perpendicular to is perpendicular to propagationpropagation
longitudinal: disturbance longitudinal: disturbance is parallel to propagationis parallel to propagation
24) a) vertically, 24) a) vertically, perpendicular to wave perpendicular to wave motionmotion
b) transverseb) transverse
25) Longitudinal25) Longitudinal26) One wavelength26) One wavelength27) 1/3 s; 3 Hz27) 1/3 s; 3 Hz28) sound, water, spring…28) sound, water, spring…
light waves do not need light waves do not need medium; mechanical waves medium; mechanical waves dodo
29) Up and down; no 29) Up and down; no horizontal movementhorizontal movement
30) Half as long; stays the 30) Half as long; stays the samesame
31) Sound waves are 31) Sound waves are vibration of particles…no vibration of particles…no particle no propagationparticle no propagation
32) neither; constant in given 32) neither; constant in given mediummedium
HWKHWK Pg 371Pg 371
3) 2700 N/m3) 2700 N/m
4) 81 N4) 81 N Section ReviewSection Review
1)1) CC
2)2) 0.52 N0.52 N
3)3) F and a F and a decreases; v decreases; v increasesincreases
4)4) momentummomentum
Pg 379Pg 379
3) 3.6 m3) 3.6 m
4) a) 3.749 s; 4) a) 3.749 s; 0.2667 Hz0.2667 Hz
b) 3.754 s; b) 3.754 s; 0.2664 Hz0.2664 Hz
c) 3.758 s, c) 3.758 s, 0.2661 Hz0.2661 Hz
HWKHWK
Pg 381Pg 381
3) 39.7 N/m3) 39.7 N/m
4) 0.869 s4) 0.869 s
5) a) 1.7 s; 0.59 Hz5) a) 1.7 s; 0.59 Hz
b) 0.14 s; 7.1 Hzb) 0.14 s; 7.1 Hz
c) 1.6 s; 0.62 Hzc) 1.6 s; 0.62 Hz
Section ReviewSection Review
1)1) 3.0 Hz; 0.33 s3.0 Hz; 0.33 s
2)2) 3.2 s; 0.31 Hz3.2 s; 0.31 Hz
3)3) 25 N/m; 1.1 s25 N/m; 1.1 s
4)4) Larger mass…Larger mass…greater periodgreater period
Wave EquationWave Equation
Speed = frequency x wavelengthSpeed = frequency x wavelength
c = f c = f v = f v = f
c = speed of light = 3.0 x 10 c = speed of light = 3.0 x 10 88 m/s m/s
WAVE INTERFERENCEWAVE INTERFERENCE
Energy travels…NOT matter Superposition Principle: two or more
waves will combine algebraically Waves pass through without altering
their shapes and size.
WAVE BEHAVIORWAVE BEHAVIOR Determining behavior when wave Determining behavior when wave
reaches a boundary (interface reaches a boundary (interface between two medium)between two medium)
Incident pulse: incoming waveIncident pulse: incoming wave Reflected pulse: a wave bouncing off Reflected pulse: a wave bouncing off
a boundarya boundary Transmitted pulse: wave continuing Transmitted pulse: wave continuing
through to next mediumthrough to next medium UprightUpright InvertedInverted
WAVE BEHAVIORWAVE BEHAVIOR
Reflection: wave hits a boundary and returnsReflection: wave hits a boundary and returns
•Newton’s third law
•Speed and wavelength are the same
•Amplitude is smaller
WAVE BEHAVIORWAVE BEHAVIOR
•Transmitted: slower than reflected and smaller wavelength•Reflected: speed and wavelength are same as incident
WAVE BEHAVIORWAVE BEHAVIOR•Transmitted: faster and larger wavelength•Reflected: same speed and wavelength as incident
WAVE BEHAVIORWAVE BEHAVIOR
RefractionRefraction: change in direction of : change in direction of waves traveling from one medium to waves traveling from one medium to anotheranother
Speed and wavelength changesSpeed and wavelength changes
WAVE BEHAVIORWAVE BEHAVIOR
DiffractionDiffraction: change in direction of : change in direction of waves as the wave passes through waves as the wave passes through opening or around a barrier.opening or around a barrier.
SOUND WAVESSOUND WAVES
Compressional or longitudinal waveCompressional or longitudinal wave High pressure and low pressure regionHigh pressure and low pressure region Speed depends on mediumSpeed depends on medium
vvsolidsolid > v > vliquidliquid> v> vgasgas
Speed depends on temperatureSpeed depends on temperature
Direct relationshipDirect relationship
343 m/s at room temperature343 m/s at room temperature
SOUND WAVESSOUND WAVES
Range of sound 20 to 20000 HzRange of sound 20 to 20000 Hz Infrasonic, audible, ultrasonicInfrasonic, audible, ultrasonic Measured in decibelsMeasured in decibels Loudness is not intensity but related Loudness is not intensity but related
to amplitude of the waveto amplitude of the wave Energy of the wave is proportional Energy of the wave is proportional
to Ato A22
Intensity is power / areaIntensity is power / area
STANDING WAVESSTANDING WAVES Standing waves: reflected and Standing waves: reflected and
incident wave interact to appear to incident wave interact to appear to be standingbe standing
Antinodes: largest amplitudeAntinodes: largest amplitude Nodes: zero amplitudeNodes: zero amplitude
STANDING WAVESSTANDING WAVES
L =L = /2 /2
L = 2L = 2 / 2 = / 2 =
L = 3L = 3 / 2 / 2
L = 4L = 4 / 2 = 2 / 2 = 2
STANDING WAVESSTANDING WAVES
Increases by increments of Increases by increments of /2 /2 Longest wavelength: L =Longest wavelength: L = n n /2 /2
where n = 1, 2, 3, 4……where n = 1, 2, 3, 4…… Fundamental frequency: lowest Fundamental frequency: lowest
frequencyfrequencyv = f v = f f = v / f = v / = nv / 2L = nv / 2L
Harmonics: multiples of the Harmonics: multiples of the fundamental frequencyfundamental frequency
OPEN PIPESOPEN PIPES
L =L = /2 /2
L = 2L = 2 / 2 = / 2 =
L = 3L = 3 / 2 / 2
L = 4L = 4 / 2 = 2 / 2 = 2
OPEN PIPESOPEN PIPES
Increases by increments of Increases by increments of /2 /2
Longest wavelength: L =Longest wavelength: L = n n /2 /2where n = 1, 2, 3, 4……where n = 1, 2, 3, 4……
Fundamental frequency: Fundamental frequency: lowest frequencylowest frequency
v = f v = f f = v / f = v / = nv / 2L = nv / 2L
CLOSED PIPESCLOSED PIPES
Increases by increments of Increases by increments of /2 /2
Longest wavelength: L =Longest wavelength: L = n n /4 /4where n = 1, 3, 5……where n = 1, 3, 5……
Fundamental frequency: Fundamental frequency: lowest frequencylowest frequency
v = f v = f f = v / f = v / = nv / 4L = nv / 4L
DOPPLER EFFECTDOPPLER EFFECT
ApproachingApproaching Wavelength decreasesWavelength decreases Speed constantSpeed constant Frequency increasesFrequency increases Pitch = frequencyPitch = frequency
LeavingLeaving Wavelength increasesWavelength increases Speed constantSpeed constant Frequency decreasesFrequency decreases
DOPPLER EFFECTDOPPLER EFFECT
Determine the movement of Stars and PlanetsDetermine the movement of Stars and Planets Blue ShiftBlue Shift
wavelength decreaseswavelength decreasesfrequency increasesfrequency increasesapproachingapproaching
Red ShiftRed Shiftwavelength increaseswavelength increasesfrequency decreasesfrequency decreasesleavingleaving
BOW/SHOCK WAVESBOW/SHOCK WAVES
Bow waves: waves overlap at the edges and Bow waves: waves overlap at the edges and the pattern made by the overlapping waves is a the pattern made by the overlapping waves is a V shape; 2-DV shape; 2-D
Shock waves: 3-DShock waves: 3-D Sonic boom: sharp crack heard when the Sonic boom: sharp crack heard when the
object breaks the overlapping waves barrierobject breaks the overlapping waves barrier
RESONANCERESONANCE
Natural frequency: frequency in Natural frequency: frequency in which an object vibrates when hitwhich an object vibrates when hit
Resonance: vibrating object Resonance: vibrating object matches the natural frequency of matches the natural frequency of an object and increasing the an object and increasing the amplitudeamplitude
BEATSBEATS
Two or more sounds Two or more sounds wave interfere wave interfere constructively or constructively or destructively producing destructively producing sound as beatssound as beats
Beats = |fBeats = |f11 – f – f22||
Pg 434Pg 4341) Air molecules vibrate parallel to motion1) Air molecules vibrate parallel to motion2) Three crests = compression; 2 troughs = 2) Three crests = compression; 2 troughs =
rarefactionrarefaction3) F = measure of rate of particle vibrate; pitch 3) F = measure of rate of particle vibrate; pitch
subjective measuresubjective measure4) Infrasonic is below 20 Hz; audible is between 20 4) Infrasonic is below 20 Hz; audible is between 20
– 20000 Hz; ultrasonic is above 20000 Hz– 20000 Hz; ultrasonic is above 20000 Hz5) Molecules move faster and collide more often5) Molecules move faster and collide more often6) Decrease6) Decrease7) Short wavelengths can image small object7) Short wavelengths can image small object8) 2F; v is constant 8) 2F; v is constant 9) Sound travels faster in solids9) Sound travels faster in solids10) Reach you at the same time10) Reach you at the same time11) Driver of the van11) Driver of the van12) Greater than 40 kHz12) Greater than 40 kHz
Pg 434Pg 43422) 70 dB22) 70 dB23) 7.96 x 1023) 7.96 x 10-2-2 W/m W/m22
24) Lowest possible frequency; multiples of the 24) Lowest possible frequency; multiples of the fundamental frequency fundamental frequency
25)4.0 m, 2.0 m, 1.3 m, 1.0 m25)4.0 m, 2.0 m, 1.3 m, 1.0 m26) Closed end has a node; open end has antinode26) Closed end has a node; open end has antinode27) Variation in intensity levels27) Variation in intensity levels28) Transfer vibration to air at different intensity 28) Transfer vibration to air at different intensity
levelslevels29) 3 Hz29) 3 Hz30) Change length of the air column, changing the 30) Change length of the air column, changing the
fundamental frequencyfundamental frequency31) yes, difference equals to fundamental frequency 31) yes, difference equals to fundamental frequency
for open pipes and twice fundamental frequency for open pipes and twice fundamental frequency for closed pipesfor closed pipes
32) Flute: 2L; clarinet: 4L; speed of sound is same; 32) Flute: 2L; clarinet: 4L; speed of sound is same; flute’s f = 2 clarinet fflute’s f = 2 clarinet f