NOTES



Notes:Name: __________________________Stamps:Period: _________NotesWaves - SoundDirections: Fill in the blanks and boxes in the note panel. After notes are done, part of your homework is to fill in the sides with study questions and write a summary that demonstrates you understand what is important in the notes.Wave Equations QuestionsMain NotesWave: The transfer of ____________ without the transfer of ____________.Wave Diagram – # of wavelengths in the wave below_____-2413098425The Wave Equationsfrequency ( f )= how many ____________________ pass per second = How often, or frequent, something occurs units: hertz (Hz) = period ( T )= time it takes for 1 __________________ to pass byunits: speed ( v ) = How __________ something movesunits:Example 1:The wave above takes 10 seconds to pass by.What is its period?What is its frequency?Summary:Types of WavesQuestions / main ideasMain Notes? Mechanical waves require ___________ (a medium) in order to travelExamples: ? Electromagnetic waves ____________ require a medium. They can travel through empty space. Mechanical Wave TypesTransverse Wave: medium vibrates _______________________ the direction the energy moves.9017013970Longitudinal Wave: medium vibrates _______________________ the direction the energy moves. 1651011811000Classify the following mechanical waves as transverse or longitudinal:A wave at a ball gameGuitar stringFlag waving in the windSound waveShaking a ropeWater waveSlinkyTransverseLongitudinal Electromagnetic Waves400055969000? All EM waves travel at ______________m/s? Radio Waves: ________________in the EM spectrum? Visible light is a tiny section of the EM spectrum ? Visible light is between __________________ and _______________Example:The diagrams below represent two periodic waves traveling in a uniform medium. AWhat type of wave is shown above?2m3305810471424000BWhat is the wavelength of wave A?448310474599000What is the wavelength of wave B?Summary:InterferenceQuestionsMain Notessuperposition: when two or more waves _________________? Waves do not affect each other’s _______________This is why you can hear lines in a song. ? When superimposed, overall amplitude is the _________ of individual wave amplitudesThis explains why it gets louder when many people talk at once.Draw each wave pulse before, during and after they meet.BEFORE26860584455DURINGWaves above the rest position are positiveWaves below the rest position are _________Add them up26797041910AFTERWaves pass through each other unaffected267970133350Summary:Sound – volume and pitchQuestions / Main ideasMain Notes? Sound is a ________________ wave? Speed depends on both the _______________ and temperature ? Fastest in _________________ (6000 m/s in steel)? Slower in _________________ (1500 m/s in water) ? Slowest in gasesSpeed of sound in air ? v = __________m/s at 0° Cat average temp: 20° C, v = If no temperature is given, assume the temperature is ___________Example:If you hear lightning strike 3.0 seconds after seeing it, how far away did it strike?___________________________________________________Characterizing SoundSound waves are characterized by:Pitch – “high” or “low” sounds? Depends on _________________? Young healthy human ear has a range of 20 Hz to 20,000 Hz? Human voice: 120 Hz to 20,000 Hz? Baby cry: 2000 Hz to 3000 HzFrequency and pitch are important in music? In music, an ______________is a doubling in fContinuous dBPermissible exposure 858 hours884 hours912 hours941 hour9730 min10015 min1037.5 min1063.75 min (<4 min)1091.875 min (<2 min)1120.9375 min (~1 min)1150.46875 min (~30 sec)Volume (loudness) ? Depends on the ______________ of a sound wave? new unit _______________ (db)? The decibel is based on human hearing? 0 decibels is the threshold of ___________? Threshold is the quietist sound you can hear ? 140 is the sound of a jet on a runway? decibel scale is __________________? So, 60 db 70 db means 10 louder? 60 db 80 db means 100 louder? 0 db to 140 db is 100,000,000,000,000x louderSound AAnalyzing Sound WavesFor which sound(s) would you hear the lowest volume? Sound BFor which sound(s) would you hear the lowest pitch?Sound C3. If you hear Sound B and Sound C what will be the same? What will be different?Summary:Doppler EffectQuestionsMain Notes in front is ______________ than the in backStationary Source1276353175 in front is ______________ than the in backMoving Source – where would you stand to hear a higher pitch?71183510477500Doppler Effect occurs if either ____________ or ____________ is moving.14033525400??’ = frequency the ___________ hears?? = actual frequency of ___________ ?v = speed of sound (___________ )?vo = speed of ___________ ?vs = speed of ___________ Picking SignsEx: On a day when the speed of sound is 350 m/s, a police car with a 2,000 Hz siren and a speed of 35 m/s is chasing a car moving at 50 m/s. What frequency does the driver of the car hear?What is the source?What is the observer?? =v =vo =vs =Given:596900153035Time to pick signs!NumeratorIf observer travels away from source, pitch goes _______?for pitch to go __________, vo must be __________If observer travels towards source, pitch goes ________?for pitch to go __________, vo must be __________DenominatorIf source travels away from observer, pitch goes _______?for pitch to go __________, vs must be __________If source travels toward observer, pitch goes _______?for pitch to go __________, vs must be __________Our observer is moving ______________ source ( )Our source is moving ______________ observer ( )observer hears a ______________ pitchSummary:When the Source is faster than the SoundQuestionsMain NotesMach Speed (pronounced: mock)A plane traveling at the speed of sound is traveling at ___________NASA space shuttles travel at ________ – that’s 25 times the speed of sound!Sonic BoomsObjects moving faster than sound create shock waves from the compressed air.An observer hears this as a ___________ or BOOM!The boom is caused by multiple overlapping wave crests which ____________ interfere3432175-137985500Which plane is moving faster?2653665222258890025400The four figures below represent sound waves emitted by moving source. 609602540001. Which picture(s) represent(s) a source moving at less than the speed of sound?2. Which picture(s) represent(s) a source moving at the speed of sound?3. Which picture(s) represent(s) a source moving faster than the speed of sound?Summary:Standing Waves & ResonanceQuestionsMain NotesStanding Waves? Occur when two waves _____________ each other? The second wave is usually a _________________? The _____ and _____ of each wave must be equalcenter381000? The parts that are motionless are called _________________Points _____________ are nodes? The parts where A reaches a maximum are called _________________Points ____________ are antinodesThe simplest standing wave (Wave A) is called the fundamentalWave A is in the ____________ of vibration274574022923500Wave B is in the 2nd mode Wave C is in the 3rd modeQuestions1. Which standing wave has the greatest wavelength2. The shortest?3. How many wavelengths are shown in each standing wave? Ex: If the string above is 3 m long and in first mode of vibration (A), what is the wavelength of the standing wave? ResonanceMost physical systems have a __________________, which are easy to excite? Vibrations keep moving if driven at their natural frequency? This produces ____________wavesExamples of Resonance: 1.2.3.4.Changes in MediumsWaves ________ & change _______ when they change mediumsReflected wave creates standing waves (resonance)Transmitted wave is what you hearWave Speed3514725-108458000Wave speed depends on the _________ and _________ of the mediumWaves in Strings travel _________ than waves in Air (Strings are more dense than air)Waves in Stings travel _________ than waves in Wood(Strings are less dense than air)Wave ReflectionReflected waves create __________ waves (resonance)Waves traveling from String to Wood bridge of a violin Less More dense: Reflection is closed and ___________Waves traveling from constricted air (tuba or flute) to free air More Less dense: Reflection is open and ____________Wave Reflection & Transmission Summary:BeatsQuestionsMain Notes?? A beat is an oscillation in ____________ ? Beats are caused by constructive and destructive __________6877058636000? Let’s look at two tuning forks at slightly different ________________? The alternation between loud and soft is caused by _____________3328842616200057340560452000??The beat frequency (______________) is equal to the _____________ in frequencies of the two tonesExample: If two people stood near each other and whistled, one with a frequency of 204 Hz and the other with a frequency of 214 Hz, how many beats would people hear in 10 seconds?Within 1 second you would hear ___ beatsIn 2 seconds you would hear ___beatsSo, within 10 seconds you would hear ____ beats Summary Polarized LightQuestionsMain NotesLight is a ____________ waveThe wave below shows how this would appear788670641350036715701333500369760533083500If we looked at this wave head on it would appear as a line going up and downNaturally occurring light has waves on _______________118300513335000This type of light is called ______________ lightPolarized light is made of waves vibrating in _________ plane27819357683500Let’s imagine unpolarized light in just ________ planes of vibrationVertical wave drawn as an arrow Horizontal wave drawn as a dotHow do you get Polarized light? There are 3 methods of polarization:Selective Absorption ______________________Double Refraction Selective AbsorptionA film of molecules stretched out in same ___________These molecules absorb all the light in that _________Remaining 50% (perpendicular to molecules) passes through the film401955148590002 filters lined up 90° to each other will block _______%ReflectionThe horizontal component of light tends to ___________ off transparent surfaces (glare)The vertical component of light tends to ____________Not a perfect polarizationWhen the reflected ray and the refracted ray are 90° from each other…They are both totally polarized 9544051206500Polarizing SunglassesPolarized sunglasses only block light that is vibrating ____________ (the glare)Real polarizing sunglasses will not work if you turn your head 698502921000Double RefractionVertical component and horizontal component refract ___________38290515748000This gives two separate polarized raysAll light is blocked out with two ________________ filtersOne ___________ out the horizontal the other the verticalStress lines shown if it is a double refractorSummary: ................
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