Merken
Basic Physics III Lecture 5
Automatisierte Medienanalyse
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Erkannte Entitäten
Sprachtranskript
00:05
No we will continue our discussion off A wave phenomenon and the 1st thing I'd like to talk about it A reflection of waves solidarity observation is that waves had an obstacle for the end of the medium all bond between media van our reflection of the yield curve which means that these waves reverses
00:32
Directions for a very good example is An echo from a distance cliff where can you yourself shopping sometimes Sometimes there if you watch carefully a beach you can even see a seaward wave after grave crashed on solar on here's how wave reflection happens in the the onedimensional case so again we consider talks strained and it is fixed at this and some ways This is moving in and it's heading this and has nowhere to go and what happened This is where legal Around here and then reflects with an inverted shape the pulse was positive Before it becomes negative after And viceversa members of positive after also issued just however Lucy hanging role The amount of them what happens is that the wave reflected on this Case and the shape of The rate of this modern work so it comes The forests are going up before it is also going up after but in both Case Whether fix the end of this and a some reflected received a more complicated case is that if a wave moves from 1 Media winter different For example again on the example of the B role he can have a female role opened and and the figure so this 1 has more long linear mast Institute in this 1 and barefoot Therefore we waves speeds on different in this light sex compared with heavy and In that case what will happen is that part of the way Transmitted Into that every section and Part of the way is reflected back And of course there since at the boundary this Point here with pool sections patch and the frequency of both ways that has to be the same the frequencies Of the wave doesn't change it is just that the wavelength If you have a son of Saudi away in at in the transmitted pulse will be different than in the income So the wavelength changes because these have a product of a wavelength And frequency must be the same and the frequency does not see ahead of fourdimensional threedimensional way that we can define airways France and Bay France are basically all the points that form of the crest of a trough of away people in general all the points that have the same fate as you could connect those With of lines planes depending on the dimensionality and that is You Representation the way More weekend are defined lines said go perpendicular to those way France and those are called ladies and that will be important ones How optics the laid a trap So I'll be observed that if we have a point source somewhere close than those wave But Our curve and the Rays And go out like this however if the source is very distant then this curvature is very small Look like a parallel lines and that is called but those ways are called plane waves on threedimensional actual planes So in that Case as these arrays will also go parallel I'm not vote on the old for or In would go on So how does the higher dimensional airwaves It will be deflect air again Hit some obstacles shown here and you can now define the incident angle and the way we define an incident angle as we look at the the rate of the incoming wave and Measure the angle but it makes With respect to be normal direction of the obstacles not what erection means As the direction that perpendicular to the obstacles so this is called the incident angle or incoming Campbell and can that also define a reflected angle and that is for the out Going with the right angle that the rain makes They do want better And there's a resume simple long for our reflections of plane waves that every angle Reflection must Equal The angle of incidence of So angles must be exactly the same The mother case there's been a penetration in told a Obama in different ways Just like we had the role let's say we have a different velocity of the wave This Region compared to that agency and the way France upcoming and some anger like this again we can't define the incident and the fate of time and In this media on the way picture actually have a slowdown and Therefore we wave changes Directions and the transmitted wave changes and There's lawful refraction also the dispose of she just like there was a lawful reflection and that offer fraction is that The race Show off the site of the incident and Although the sign of a refracted and must be equal to the ratio of the velocity in this The you that and you will hear more about this all refraction and chapter the cover off And that is Cadillac tools of the 3rd thing when tender obstacle when you put an obstacle and multidimensional wave I like this way it's coming this you observe that way seemed to sort a floor on the obstacle to just uh Think of ways The rains This is hard to understand because You would think OK just travels like this We can define a shadow Behind that obstacle when you look at race would think that it go into the shadow but a real is actually the band around a little bit and sell sometimes if you will probably behind the obdurate France actually reform as if nothing has happened that called diffraction and how much the way it can Penetrated shadow But floor on the obstacles that depends on wavelength and as it happens depends of roughly estimate how far that by defining some bending angle on much weight actually has depend on The object and that should be given by about the size of the wavelengths divided by the size of the object So again we will you more about that later chapters in the both asked that now come back To a point that We discussed at the very beginning that There's a difference between the way the speed and the speed of the particle so if we consider these rope example again and final Saudi away Couldn't abide by this expression than in all the the waves speed is given by the ratio of On the Gulf pay But added Tom rope particles of atrocities by over a different expression and Force For ease off discussion let's just consider 1 particular point X 0 0 brick any point Derek keep it fixed rare midfield
09:38
At this this formula because we right just like this For putting BKX And the fine and parenthesis and that Basically just looks like a fixed Angle in this simple harmonic motion so we have basically simple harmonic motion With Some constant in here which is the base of the simple harmonic and northern what the velocity it's That's the symbol So assigned becomes a cosigner Andy A picture of when extra fact outside All we can added termed the acceleration Doing will time derivatives Drive this again and another Oh my God appears And the Becomes now a minus sign and we can then express the fact of The only way A case where time Wave velocity square So we ever get The sliver of Samaranch Just forget them as The article Velocity expression 8 times on KX bus bombing that he find drop 0 and X because now I am again considering any point since I can repeat this exercise for every such world it holds actually fall Point and symbolically right this is partial Derivative of the function was that time And begin ordered that Those for the meaning of this symbol a simple eating the same as the Uvalda Roberto but be that Where At 1 moment we only consider 1 particular position acts Exs Constant probably performed the time and zoom only the 2nd partial but time derivative are particle acceleration which has an air AT Omega square the miners SunTimes signed KX on the phone And if you pick Away That goes in the opposite direction this 1 troubles actually From left to pick 1 the troubles right then To get very similar expressions only be a Iong ago on that term changes sign you get an extra side so of course we could do a lawyer A similar trip looking instead of At that time to look at The position from now need to focus on 1 instant in time and that confidence and And look At a pulse frozen in time for example the here and if it takes me a derivative of the talks with respect to lead Position than that This something like the smoke on March the pulse slopes forms on a positive slope of the negative somewhere over there would have to put on and The 2nd derivative the changeover And that is something like how much does the role And so I feel for example it doesn't have banded all year bands of it'll be formed from this direction that Up appear at the top it bends a lot because it goes from up to and this Curvature is important because it is actually defining how much for force Uh acts in the transverse direction on the part of transfers direction along with the sole either curvature you'll have more for us for example he would have a lot of curvature we have these Tension force going this way At this point in this way at that point and We combine those forces we get a lot of large Dong pointing transfer or if they have no curvature like healed Those 2 forces are cancel each other out There is no France was forced at all and if they have just a little bit of curvature here with the courage of The opens the other way and therefore the resulting forests pointing up but is smaller than at risk So in general and be the curvature is portion of the force or another words The transfer of course It a potential force times So we can then and a similar expressions for an open the forest For the year and velocity and that Acceleration of gold particles only that this time we to look at X rather than he gave ever similar looking expressions and again We make this funny symbol that We have a partial derivative with respect space and what it means is that while performing the Derivative a only look at 1 instant in time and There was some Osorio leaves at least goes to Formula 1 for time and the 1 of the space look for a similar adjusted different prefab solar before we had an armored square And now we have a case case square And These strong new ideas again for the right traveling so we can put this together with With A Newton's law which tells us that The last time acceleration equals force in this case must density times world Particles transfer Acceleration equals the transfer of force which is the tension force times the curvature and formally me right righted like this which is year the wave equation and this equation is valid actually for signed since they know all that This will last Which is the ratio of these tension force are divided by Masters 2 Yeah Can be also plays in the case of some sort of by the ratio of armor got the the angular frequency all the way and so this wave equation is fulfilled son Osorio and as it turns out It is fulfilled by any general calls U. And generally so what it should remember from from this Discussion he expression for the particle velocity and acceleration and the fact that We wave equation is nothing else But Newton's 2nd law that must density times particle acceleration for become tool and other characteristics But a Waves that all such immigration and that is the principal Superposition we can ask ourselves what happens if you have multiple waves that passed with the same regional space At the same time and that is called the principle of superposition what it means Is that became Simply add a bit deflections each of which awaits just like a are normal additional Displacement is a strictly true only for Libya medium and linear media there are those that result in a waiver creations like the 1 just what it basically means is that Wave speed is independent On things like the amplitude in such a case the sum of all wave functions of several wave functions Always away function also have formed the combined weight since buyers and the additional separate and in particular a multiple of functions also of between make this a bit more concrete by looking at the 3rd Demonstration program let's assume that we have told pulses that A trouble from a very to pollsters that trouble from the left and from the right of the green screen
19:05
Against each other It at church If you are The still see the components as the Bruins red But now they actually marriage and a former bigger pulse in the center and since then drifting apart after that They have penetrated childless If nothing has happened and that is another feature of linearly that waves are superimposed after that a more wrong occupy the same space they not changed So as not interest in case and that is what happens if 1 hole Pulse goes up and the other 1 goes down Look at that so rules The pool pulsed stays the same but the red pulse is now I actually Umberto what happens in that case on reviewed what happens in that Case They stop to cancel each other when they're just at the right position than they actually are Cancel each other out completely And this is called a destructive interference the other cases called constructive constructive interference leads to lots of calls destructive interference No pulse of all stories up chances Let's not look That at actual sign was so always And 1st sequences of Them going in the same age End What you are seeing where he is on the way Because the red Hiding under the green is actually sum of the text If now introduce a phase difference between those those wastes the blue and red mud can actually see both of them and they are still sort of Constructive interference because some of those most was bigger than you know 1 of them but as I'm increasing the phase Difference Between them And they have positive result in post Publicist get smaller and smaller until they can Other won't completely So this is Joe we'll have to wait and see but the resultant Almost The stress Let's go go back to that Point and we have a particular superposition which is called interference and Sort of several cases for me that have are cases where the police's and Hansel and we get a destructive and all are now where they cause vying to get constructive Also if We Phases Between them and any other Alberta among between expect Our cancelation perfect edition that we get possibly destructive and also After repulsive Nor on occupy the same space me I'm and continued their troubled just for what this
23:25
Superposition principle That makes possible
23:28
This we can actually make up that kind of Wave forms A sine wave although time For example if I had 1 sign that looks like that in the 2nd round that like that and the 3rd 1 that looks like that and they all add Together then we get a weird shaped pulses look like that it's almost like a sort All are different kind of these they can combine to make something that looks A similar to square all 1 can and look at it the other way and start the script calls Asked Oneself what kind of sign on a solid deal with the required to make up for that I have another program this kind of idea this is called fullyear analysis of for
24:30
We can start with a step function and ask so how can I get such a step function although son Osorio ways and I start with the 1st son so it just looks like a straight line bronze at the 2nd want it doesn't look like this where polls at all 3rd 1 doesn't help but the 4th 1 are we had some of those pulses actually the McGrady line and starts in lieu of a little bit more similar than the square pulse And If I keep adding components But let me for ease of doing not no longer sure the individual components but it looks more and more like a like a square pass However there are many components and there will always remain on some little features The wounded our looks almost like noise that is sitting on top of those Pots Also we can now look at other parts ships for example Thought to And this will have different components of the components for assault then now than we had 4 square pots And as theirs Previously if I Have fewer components than the deviation between a desired shape Which is just straight sought to tools and the actual shape that I sort of produced the um that this method is is larger than if I have many crumpled all we can now look But such a rigid his Case consists of Robert Connected and that is easier for the sign waste were produced Even with just 6 components and add to the problem of so let's come back to To lead an interference offer of waves as has said before that we have 3 cases deconstructed the destructive for harsher destructive where a constructive interference happens face shared between them the tow individual and destructive happens if there is a phase shift of 180 degrees and A partially destructiveness There's any phase shift in between those 2 pigs Is not just No phase shift And 180 degrees but it can also be 360 degrees or For the constructive interference or 270 degrees for the destructive So I after all this technical details I on cellular different type of interference and this is interference that happens when a wave in the our interferes with its own reflection and you might remember however that there was little demand straight of waves at the beginning of the But now I'm going to do it differently so I what happens When the conditions are just right in the case of reflection always with an excited Resonance in this system of The taught world find that The smell and to see that Is sort of us standing wave only 1 that has with just of A fixed with Have happened that doesn't seem to but it's not just 1 resonance frequencies like Siena discussed in this system has many resonance frequencies and they have it has Different types of vibrate fell in this case is that the center of the world is actually not moving and again for comparison loses the other kind of mold where you have maximum movements in the middle There's just no movement we have for such spending Braves Trimble's arbitration on mode ahead of old At the end because that is where the role fixed so it can't move at Beaver the post therefore that we must have My Rivadavia vibrational mode must feel Such a way that there's no movement he and Mn in between those who will receive a large and motion which are called an entire and Additional No awards which are going places The media string doesn't appear to move at all and we can characterize vibrational mode Standing wave by harmony in all of them and their art and as a sort of ruled that each The old each and Followed by mail order and each No notice followed by And of course there's always an old And by the way such Modes exist also bought for music instruments usable could live for the try and excited fundamental In Assumption ball It is using kind of that At the end of his mother New Enzo The strained There's a little emotion and new little there's a lot of and the taste of such a music instrument be the other resonant modes are suppressed And so that kind of hard to excite probably won't be able to do it It all And And That There Well you can see it but that tends to be aired roughly this place he attends an old which before was there enough money that's it So for the for those standing waves we have doubled all modes of vibration and A pattern can be characterized by calling a note and Part that hat and each each of them those Happens each of the modes has its own characteristic natural resonant frequency And the lowest frequency mode this is called the fundamental mode and the frequency offered called the fundamental The others are called and their fundamental is the 1st It's also called the 1st harmonic and the tones are called the 2nd 3rd 4th And so on harmonic So how can we actually know what kind of frequencies Don't Resonant frequency Arm well But Standing wave it has Picked a within the system meaning that it must produce an old those to end because both ends of fixed and time and therefore fundamental or the 1st harmonic If This 1 that's the simplest 1 that is 1 where the wavelength We will sign a Florida always goes like this And you can sort of I can think of Continuing beyond the bond of football to tape this picture
33:53
Just showed 1 instant so we have an old gear and have promote here and there 10 times now and the middle and a pencil Imagine way of continuing the best course not and not that as physical no but banned the distance from here to here would be the wavelength lambda and therefore the distance from him here just half of weight so in general the distance from from 1 note for note
34:44
The next known is onehalf of The waves and the distance from an old twin and time is a quota of forward and since the yeah Ends fixed therefore that tool Knowles so a fundamental wavelength was given by the length equals Exactly 1 half of the late or the Lambda won the 1st fundamental wavelength must be equal Twice the length so that if you now will go to a higher order mode auto and all but told them that we pick up on additional node in the middle of summer we have a tool and time no and 1 over the middle and 1 Beginning in 1 order and so in this case LONDON tool is equal to the length of Mao the wavelength fits exactly Inside the little boundaries inside the length The World Solar member toll equals length and All we can also say that equal to twice the length Divided by tool so it's kind of like me fundamental wavelength divided by the number 2 We can then moved to the next hole but we have to know In the middle 2 at the end so for of together and the Yantai notes in between and get That wavelength Twothirds But The length and Therefore we have land The equals at twice the length divided by sweet orange general The wavelength The end oldest twice the length of the world divided by some number and invert this But That'll get if he was seen as a creation a frequency Times uh Lambert equals velocity than we can get the frequencies associated with those wavelengths and we find that the old homes are integral multiples Of fundamental frequency and the fundamental frequencies Given by the varsity always twice
00:00
Potenzialausgleich
Magnet
Messung
Mikrowellentechnik
Interstellares Gas
Konfektionsgröße
Linearmotor
Wasserbeckenreaktor
Leitungstheorie
Gedeckter Güterwagen
Hobel
Fahrgeschwindigkeit
Einbandmaterial
Seil
Linearmotor
Wellenlänge
Kaltumformen
Seil
Rollsteig
Schatten
Längenmessung
Crestfaktor
Demultiplexer
Teilchenfalle
Energielücke
Elektronische Medien
Übungsmunition
Werkzeug
Funksender
Werkstatt
Reflexionskoeffizient
Atmosphäre
Anstellwinkel
Interstellares Gas
Anstellwinkel
Gewicht
Tonfrequenz
Fahrgeschwindigkeit
Wellenlänge
Hobel
Teilchen
Lichtbrechung
Funksender
Beugungsfigur
Astronaut
Pfadfinder <Flugzeug>
Winter
PatchAntenne
Elementarteilchenphysik
Crestfaktor
Starkregen
Energielücke
Front <Meteorologie>
Papierstaubung
Tonnenleger
Schiffsmast
Spiel <Technik>
Tonfrequenz
Schatten
ElektronenEnergieverlustspektroskopie
Rauschzahl
Juni
Source <Elektronik>
Lichtbrechung
Phasengesteuerte Antennengruppe
Gleichstrom
Mikrowelle
Source <Elektronik>
Ersatzteil
Reflexion <Physik>
Masse <Physik>
Schwingungsphase
Unterwasserfahrzeug
09:38
Magnetisches Dipolmoment
Interstellares Gas
Siebdruck
Leisten
Linearmotor
Spannungsabhängigkeit
Kaliber <Walzwerk>
Bett
Spitze <Textilien>
Trenntechnik
Fahrgeschwindigkeit
Linearmotor
Seil
Multiplizität
Kaltumformen
Paarerzeugung
Teilchenbeschleunigung
Sonnenenergie
Übertragungsverhalten
Übungsmunition
Elektronische Medien
Lumineszenzdiode
Panzerung
Werkzeug
Regentropfen
Transversalwelle
Atmosphäre
Schwimmer <Technik>
Jahr
Elektronische Medien
Frequenzumrichter
Anstellwinkel
Drosselklappe
Gewicht
Takelage
Bergmann
Tonfrequenz
Wellenlänge
Auslenkung
Teilchen
Gasturbine
Leistungsdiode
Elementarteilchenphysik
Energielücke
DAB <Rundfunktechnik>
Edelsteinindustrie
Teilchen
Gasdichte
Mark <Maßeinheit>
Oberschwingung
Steckdose
Druckkraft
HallEffekt
Gleichstrom
Dynamische Lichtstreuung
Mikrowelle
Ersatzteil
Autobombe
Schwingungsphase
18:59
Elastische Spannung
Pelz
Elektronisches Bauelement
Astronom
Interferenz <Physik>
Wellenlänge
Übungsmunition
Wasserbeckenreaktor
Schwarzes Loch
Trenntechnik
Mikrowelle
Stunde
Astronaut
Lineal
Elektronische Medien
Elementarteilchenphysik
Linearmotor
Interferenzerscheinung
Interferenzerscheinung
23:28
Potenzialausgleich
Drehen
Kugelblitz
Satz <Drucktechnik>
Leitungstheorie
Abformung
Uhrwerk
Steckkarte
Höhentief
Patrone <Munition>
Wellenlänge
Massenresonanz
Elektronisches Bauelement
Fertigungsinsel
Rauschsignal
DHC2 Beaver
Drachenpunkt
Messgerät
Elektronische Medien
Übungsmunition
TEMWelle
Werkzeug
Angeregtes Atom
Reflexionskoeffizient
Schiff
Öffentliches Verkehrsmittel
Schleppen
Ringgeflecht
Interferenzerscheinung
Stringtheorie
Tonfrequenz
Interferenz <Physik>
Schnittmuster
Wellenlänge
Resonanzenergie
Öffentliches Verkehrsmittel
Armaturenbrett
Videokassette
Ton <Akustik>
Urkilogramm
Interferenzerscheinung
Cockpit
Tonfrequenz
KraftWärmeKopplung
Potentiometer
Waffentechnik
Oberschwingung
Proof <Graphische Technik>
Band <Textilien>
Sturmgewehr
Grundfrequenz
Mikrowelle
Gammabestrahlung
Ersatzteil
Reflexion <Physik>
Schwingungsphase
33:49
Gewicht
Wellenlänge
Bleistift
Grundfrequenz
Summer
Bikristall
Längenmessung
Kraftfahrzeugexport
Paarerzeugung
LambdaHyperon
Drachenpunkt
Tonfrequenz
Wellenlänge
Sonnenenergie
Drachenpunkt
Übungsmunition
TEMWelle
Werkzeug
Schwarzes Loch
Grundfrequenz
Mikrowelle
Öffentliches Verkehrsmittel
Fahrgeschwindigkeit
Elementarteilchenphysik
Multiplizität
Kraftfahrzeugexport
Metadaten
Formale Metadaten
Titel  Basic Physics III Lecture 5 
Serientitel  Basic Physics III 
Teil  5 
Anzahl der Teile  26 
Autor 
Smy, Michael

Lizenz 
CCNamensnennung  Weitergabe unter gleichen Bedingungen 3.0 Unported: Sie dürfen das Werk bzw. den Inhalt zu jedem legalen und nichtkommerziellen Zweck nutzen, verändern und in unveränderter oder veränderter Form vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen und das Werk bzw. diesen Inhalt auch in veränderter Form nur unter den Bedingungen dieser Lizenz weitergeben. 
DOI  10.5446/12941 
Herausgeber  University of California Irvine (UCI) 
Erscheinungsjahr  2013 
Sprache  Englisch 
Inhaltliche Metadaten
Fachgebiet  Physik 