phys16 – lecture 37
DESCRIPTION
PHYS16 – Lecture 37. Ch. 16 Wave Motion. “Interference is much clearer in HD”. Oscillations pre-question. Is a bouncing ball an example of simple harmonic motion? Yes No. Oscillations pre-question. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/1.jpg)
PHYS16 – Lecture 37
Ch. 16 Wave Motion
“Interference is much clearer in HD”
![Page 2: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/2.jpg)
Oscillations pre-question
• Is a bouncing ball an example of simple harmonic motion?
A) YesB) No
![Page 3: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/3.jpg)
Oscillations pre-question
• Two kids are swinging on two swings of the same height – one kid is a little chubbier than the other. Neglecting frictional forces, which kid completes a back and forth swing in the fastest time?
A) The chubby kidB) The skinny kidC) The kid who pushes off the ground the bestD) Both complete in the same time
![Page 4: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/4.jpg)
Oscillations pre-question
• A mass on a spring is driven at a driving frequency (red curve) and the resulting position vs. time of the mass is given (blue curve). Which case is closest to resonance?
![Page 5: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/5.jpg)
Ch. 16 Wave Motion
• Mechanical Waves– Transverse vs. Longitudinal– Properties
• Example: Wave on a String– How the wave propagates– Speed– Reflection and Transmission
• Superposition and Standing Waves
![Page 6: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/6.jpg)
Waves pre-question
PhET website
![Page 7: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/7.jpg)
Waves pre-question
PhET website
0.0133
![Page 8: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/8.jpg)
Mechanical Waves
![Page 9: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/9.jpg)
Mechanical Waves
• A propagating oscillation that moves through a medium
Transverse – water waves, disturbance on a string
Longitudinal – sound waves, slinky or spring
![Page 10: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/10.jpg)
Mechanical Waves
• Waves use at least 1-3 space dimensions and time…– Ex. – Water waves propagate in x, move “up and down” in
y, and change position with time– Ex. – Sound waves propagate in x, move “up and down” in
x, and change position with time
![Page 11: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/11.jpg)
Wave Properties
• Period –
Thighperiod
mediumperiod
lowperiod
fT 12
![Page 12: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/12.jpg)
Wave Properties
• Period –
• Wavelength and Wave number –
fT 12
2
http://seagrant.uaf.edu/marine-ed/curriculum/images/stories/grade7/wave.jpg
![Page 13: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/13.jpg)
Wave Properties
• Period –• Wavelength and Wave number –
fT 12
2
http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/Images_specific/wave_def.gif
![Page 14: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/14.jpg)
Wave Properties
• Period –
• Wavelength and Wave number –
• Wave speed –
fT 12
2
http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/Images_specific/wave_def.gif
fTt
xv
![Page 15: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/15.jpg)
Ripple Tank Simulation
![Page 16: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/16.jpg)
Example: Speaker
PhET website
Speed =Period =Wave number = Wavelength =
330 m/s0.0038 s5.0m-1
1.25 m
![Page 17: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/17.jpg)
Example: Sand on a vibrating plate
• Sand is placed on the vibrating plate below. Which apparatus is vibrating the plate with the highest wave number?
![Page 18: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/18.jpg)
Wave Function or Waveform
)sin(),(22 ,
0
xtAtxyvfvvxt
Plane Wave
Higher Dimension Wave
)sin()(),( 0 xtxAtxy
![Page 19: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/19.jpg)
Wave on a String
![Page 20: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/20.jpg)
Wave on a String
• You can generate a wave on a string by pulsing sting with your hand
• Speed of pulse/wave is related to tension in string and mass density of string Tv
PhET website
![Page 21: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/21.jpg)
Propagation of Pulse• If you advance the movie one frame point A will move…
(higher, lower, right, left)?• If generate new pulse but more quickly than first then it will
be… (same, wider, narrower)?• If generate new pulse but move hand higher than first then it
will be… (same, taller, shorter)?• If generate new pulse with rope tightened then pulse will be…
(same, faster, slower)?
PhET website
![Page 22: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/22.jpg)
Wave on String Simulation
PhET website
![Page 23: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/23.jpg)
Example Question
PhET website
![Page 24: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/24.jpg)
Superposition, Interference, and Standing Waves
![Page 25: PHYS16 – Lecture 37](https://reader036.vdocuments.net/reader036/viewer/2022062302/56816450550346895dd61a4a/html5/thumbnails/25.jpg)
Main Points – Wave Properties
• Mechanical Wave – a propagating oscillation that moves through a medium Tv
• Period –
• Wavelength and Wave number –
• Wave speed –
fT 12
2
fTt
xv