Lec 31 | 8.01 Physics I: Classical Mechanics, Fall 1999

[bebeheuy]

I Love The Video It Can Increase My Knowledge Forced Oscillations - Normal Modes - Resonance - Natural Frequencies - Musical Instruments

[Mjhond]

Steady I Really Like This Video Forced Oscillations - Normal Modes - Resonance - Natural Frequencies - Musical Instruments

[lllBOLTlll]

MIT student or anyone smart! when using the mx''+kx=Focos(wt) .... For the glass experiment with the frequency 470 Hz. What is my Mass m. (lbs,g,kg,Newtons?), and what is my k(wo^2 or is it solved in Wo=sqrt(k/m) and is it in lb/s,m/s, N/s, ???). And finally my Fo is what?(amplitude???? is it in radians/sec, Hz?????) I NEED HELP SOON

[behnamasid]

love the helium talk...

[annmardun]

tacoma narrows did not collapse as a result of resonance...

[unfreez]

Look up the Danish engineer "Allan Larsen" he has found the exact reason why the bridge collapsed. It's a matter of aerodynamics but also in fact resonance

[annmardun]

@unfreez i swear it was not resonance... look at report by Billah and Scanlan.

resonance is often wrongly associated with the bridge. it was as a result of self excitation... then look at all the journals they refer to that support self excitation

[unfreez]

@annmardun I don't mean that the winds frequency made the bridge oscillate not at all.

The thing is that the bridge had flat sides, that the wind could create whirls over, when a whirl is created, it tries to get back out in the flow and that creates an upright force, when the bridge is up, whirls starts to form on the underside which will create a downright force. This will continue and the bridge will break.

[annmardun]

@unfreez yes that is true but that was not the destructive vibrations of the bridge. and yes the side plate girders were the main reason for the aerodynamic instability, but the bridge began to experience torsional motion when the wind speed increased and then the amplitudes increased due to self excitation, ie negative damping and the bridge then collapsed. no resonance

[Vlogging4Jogging]

X double-dot? Why?

[BenG549]

@Vlogging4Jogging A dot is usually used to express a derivative with respect to time, hence X double dot would be the 2nd derivative of displacement (X), with respect to time i.e. acceleration.

[cappylog1]

...

[MeestPig]

Crazy how people apply themselves and learn this stuff.

[noobtuberize]

ummm.... im 13 lol

[RazorRabidz]

I feel so stupid.

[itachicrasian2]

how do you make the dotted lines so quickly O.o

[aleks5005]

why do i always learn more by watching videos then sitting in class

[Xytos]

20:25 im surprised no one's made a joke about that lol

[FlavoredCoffeeGuy]

you couldn't know there was a difference until you hit a dispersive medium like opal.

[FlavoredCoffeeGuy]

No more laser rods, laser cubes.

[FlavoredCoffeeGuy]

So, wouldn't a Michealson's Interferometer be more ideal for construct for a high energy laser if the light can re-enter and 50% reset to being 180 degrees out of phase? If none of the energy is lost destructive interference only acts as a means of storage. Not zero point energy, forced zero point energy storage.

[FlavoredCoffeeGuy]

If I have a cylinder that's 1 meter long .3 meters in diameter filled with water and drive it at it's resonant frequency based upon the speed of sound through water. I drive it at both ends and the resulting standing waves should be 180 out of phase. How much energy can build up if the sum is zero. What is the limit that the chamber can handle, and to what is the energy converted to if it has not been destroyed.

[smartdon007]

Damn...he still uses a chalk and black board....!

[theanimefreakazoid]

This prof makes me like physics. Totally worth the watch.

[cobolt13]

I failed Grade 11 math. Now I'm watching MIT physics. I must be smart.

[philnoll]

Wow, this guy is a madman with a piece of chalk. Did you all see how he drew that dotted line at 6:29? Fucking sick, dude.

[rsotbairnfire]

@philnoll Dear me that is epic! And it made a cool noise, too.

[WhiteSerpentz]

F-ZERO divided by K = FALCON PUNCH!!

Either way, why aren't there that many students in that class?

[tdocomo]

sir if you read this plz respond to it. I am a student pursuing graduation(first year) in India. Even in IIT's which are prime technological institution in my country such lectures are not given. I wonder if I could also be a lecturer like you. Plz tell me someway to get into MIT. It will be honour for me to do studies under your guidance. Also tell me about how you pursue your education, I mean which courses from where? My Email ID is shvmschdeva@gmail.com

[HunterDX77M]

@tdocomo

He's not going to respond to you from here. You are going to have to contact him using his information listed at mit.edu (search him up there). I hope that helps you get a hold of him. Good luck.

[tdocomo]

sir if you read this plz respond to it. I am a student pursuing graduation(first year) in India. Even in IIT's which are prime technological institution in my country such lectures are not given. I wonder if I could also be a lecturer like you. Plz tell me someway to get into MIT. It will be honour for me to do studies under your guidance. Also tell me about how you pursue your education, I mean which courses from where?

[samuel91222]

when he plays the wind organ...he looks a real musician.

[olliemacfarlane]

very well presented lecture, fun to watch and helping me grasp the concepts... :D

[13Maximus13]

Awesome!!

[FridayNightLights321]

Who decides they want to be a boring ass professor when they grow up? Apparently, this guy did.

[Chubigans]

I owe my deeper understanding of physics 1 to this guy's lectures.

[Chubigans]

LMFAO @ helium

[cvenator1]

i did not really watch this

[EnRage690]

duh... what ? oops sorry , wrong class, im looking for my PE instructor.

[tranthimydung203]

I just wish that I know those videos earlier

[Squatchmichael]

@tranthimydung203 You are telling me! I got my physics degree before YouTube. Too bad I had to learn the hard way.

[pieplay]

Wauw, I saw all this in highschool. Is there a sequel where they talk about the resonance frequency in mathematical solid objects? like a glass cilinder.

[Squatchmichael]

@pieplay First off, I doubt you saw *all this* in high school. And I am certain the homework is more challenging at MIT than your high school.

To answer your question, I think you are asking "is there a video where he talks about resonance in solid objects using a mathematical model". That is elasticity and acoustics. Much more difficult. A seismology book containing a chapter called "normal modes" or "spherical harmonics" will introduce you to that.

[pieplay]

@Squatchmichael

I'm not in highschool anymore, and I needed it for a project last semester. Ah well thanks anyways

[deborahzevedo]

Uauu! Essa aula foi D +! Mt esclarecedora. Amei o final! Agora estou preparada para o teste de ondas...xD

Whoa! This class was amazing! Very enlightening. I loved the end! Now I'm ready for my test about waves... xD

[lorent123]

Hey thats pretty much what i'm doing in my 3rd physics class in Cegep ( i think it's the equivalent of College here in Quebec). The professor really good! It makes me more confident about University haha, but i guess it's gets tougher...

[Kingarthur305]

Does anyone know the program name he showed on t.v about resonance on the bridge?

[Metzlerguy98]

lol 2:22

but sooner or later you will have to go with the frequency that i force myself upon you

[butterflyfreakshow]

Olibirch...It is because they know that they are getting a top notch- mind- blowing education and they are hoping they can hang on and figure out what he said later.

They also are trying to figure out how all this applies to their future at Wal Mart.

[w2wgamer]

i doubt MIT students are going to be working at walmart.

[torhjelm]

Fascinating, even though it´s all greek to me.

I expect Marty McFly to arrive with the time

machine at any second, lol.

[femzter]

da guys good!!

[olibirch]

Why do all of those students look so unhappy when they have such an awesome professor?!

[CanisLupus1987]

because they're not there for the sake of their love for Physics. It's a required part of their course and they must live with it.

I'm pretty sure if you look into more advanced level's videos you'll see that those levels will have students that really apreciate his work.

But before I go through them better revise the basics. I've been without studying physics for 7 years now... so a lot of it is gone...

[Nabo00o]

olibirch, I doubt they are unhappy, they're probably just VERY concentrated. Or at least I hope...

[Friendlysword]

How handy, if you cannot show up for class then you can just find it here :D

[evertonptube]

Kick a** professor!!

[couchpotatoe244]

that's a lot of chalkboards....

[couchpotatoe244]

say what?

[69marcus70]

wat the fuk is he on about

[sniperontheroof123]

The dot notation is just the integral? How do you know there won't be a constant in the x dot or x double dot term at 3:48 ?

[silentun]

I think the dot notations are just time derivatives, not integrals

[Yoshi0]

Silentun, what you say is true.

[PianoWallaby]

Swinging the red thing, the lowest note was the 2nd harmonic and he went up to the 6th.  I never heard the fundamental (an octave below the 2nd harmonic) .

[realyyellowsquares]

this is so boring.

[groovedance]

best lecturer i've ever seen.

wish my lecturers were that good D:

i understand everything. except i forgot how to do the derivatives :s

[Ghaisn]

understanding these concepts is one thing...communicating and expressing them in written mathematical language is another thing

[jakstrike1]

how does he do those cool dotted lines?

[sorrysonofa]

I wonder! I wish I knew how to do them

[AcolyteOfDeath]

What are you talking about? This is easy!

[airwick210]

Acolyte: this is not easy. Cook: try hard and you will understand it. None of this is trivial, and none of it is mystical stuff only super geniuses can understand. If you think it's too easy, then get permission from the department to skip this and take the next course. Eventually you'll get to where it's just about hard work.

[Cook31992]

wtf is this...who understands any of this...?

[nugebri]

hahahaha I hear ya, it's a complete different language

[PELLAPELLA]

this is SO hard. Fuck.

[ab8jeh]

man these analytical methods are a drag.

[connorbag]

i like the part where he was doing physics