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

Forced Oscillations - Normal Modes - Resonance - Natural Frequencies - Musical Instruments

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[Metzlerguy98]

lol 2:22

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

[w2wgamer]

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

[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

[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

[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 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]

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

[behnamasid]

love the helium talk...

[annmardun]

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

[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.