8.03 - Lect 4 - Forced Oscillations, Power, Resonance, Transient Solutions

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  • Опубліковано 3 січ 2025

КОМЕНТАРІ • 162

  • @pablojvazquez
    @pablojvazquez 6 років тому +41

    I've been struggling to appropriately understand "general solutions".. The way you teach how to derive the general solution is simply brilliant. Thank you so much for your generosity: always providing the best way to really understand any issue!

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  6 років тому +12

      :)

    • @unknowinglyanonymous9215
      @unknowinglyanonymous9215 3 роки тому +1

      @@lecturesbywalterlewin.they9259 sir u are op honestly my teacher used 140 slides still wasn't as clear as ur lectures and demonstration thanks a lot for this gift.

    • @guptakunal2003
      @guptakunal2003 3 роки тому +1

      @@unknowinglyanonymous9215 u in nbits

    • @alexandredemasure
      @alexandredemasure 3 роки тому +2

      I'm still confused. If I add a zero I will have a different result than if I don't ? How does it make sense ? There is something deeper hidden here

    • @comrade_marshal
      @comrade_marshal 2 роки тому

      @@alexandredemasure actually here two things happen
      1. The motion of the damped system tends to undergo its original way i.e., it behaves as if no external force is present
      2. The external force exerts its influence throughout the motion
      Basically it resembles superposition when we consider adding a zero to the differential equation to show the transient phenomenon, when the net motion is due to the constituent oscillations (external forced + internal damped)

  • @shankarshantewari4694
    @shankarshantewari4694 7 років тому +19

    These are really helping me save my semester.Thank you so much.

  • @studytonic3619
    @studytonic3619 Місяць тому +1

    I thought oscillation would be hard to study and grasp.But sir you won by heart.Thank you so much for this wonderful explanation.

  • @laupii1
    @laupii1 8 років тому +16

    Always I have an exam, I study with your lectures and I have done well.
    Thanks.

  • @pramodkharel2082
    @pramodkharel2082 4 роки тому +1

    I would have never understood SHM without your lectures. Thank you so much!!!

  • @shogu1237
    @shogu1237 6 років тому +8

    Finally I understood forced oscillatons. thanks prof.
    :):):). I hope i'll do well in physics in NEET........

  • @mkh6338
    @mkh6338 Рік тому

    I really saw through the equations! Physics owes You, you show its beauty.
    When I was a high school student I couldn't catch the point of spectrums. But now it lit up in my mind!

  • @davidabraham434
    @davidabraham434 8 років тому +3

    Very Helpful for the Imperial College first year waves and vibrations module!

  • @surendrakverma555
    @surendrakverma555 3 роки тому +2

    Excellent way of teaching Physics Sir . Thanks a lot as I am really enjoying Physics now and understanding laws of nature with online practicals. Thanks and Regards 🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏

  • @ShadowZZZ
    @ShadowZZZ 7 років тому +9

    43:43 just forgot to put an ''s'' at the end of the cosine
    and acording to 51:46 I get partial credit from prof. WL,
    without even studying there in the first place, wohoo~

  • @najahlassad8951
    @najahlassad8951 8 років тому +1

    magnificent very greate teacher of physics ,and teaching ,and reviving curiosity and wonder the most important human instenct.
    +∞ thank you sir Walter Lewin.

  • @gyaner_alo
    @gyaner_alo Місяць тому

    Bestest❤

  • @akaashs2131
    @akaashs2131 5 років тому +1

    Why are we not including the velocity from the transient solution and only including the velocity from the Steady state solution to calculate the Power in 22:37

  • @namesurn8590
    @namesurn8590 6 років тому +1

    on 55:00 you mention that for demonstration you measure voltage across small 1.7 ohm resistor. But why can't measure voltage across initial 50 ohm resistor?why need this another 1.7 ohm resistor, why it is better?
    for picture on 59:10 , why lines on right side don't converge back to 0?
    your lectures are wonderful

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  6 років тому

      I suppose we could have measured the potential diff over the 50 Ohm resister which would be proportional to I. I do not recall why we used a 1.7 Ohm resistor instead.

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  6 років тому

      >>>why lines on right side don't converge back to 0?>>>
      good question. I no longer have my notes. I gave this lecture in 2004.
      My guess is that I would continue to go down if we had increased the frequency more than we did.

    • @namesurn8590
      @namesurn8590 6 років тому

      thanks for answer
      i really your lectures because you show how equations work in real world instead of just writing random equations & doing substitutions out from nowhere (like many lecturers do).
      i follow your lectures(and PS) since 8.01 and can't even estimate how much they help me.
      Never seen better source for learing physics.

  • @and_rotate69
    @and_rotate69 3 роки тому +1

    in my university, we study vibrations and waves with the Lagrangian system, so we take gamma=b/2m

  • @FrainBart_main
    @FrainBart_main 6 років тому +1

    Thank you for another awesome lecture. If I understand the last experiment with visible light spectrum and Na gas (around 1:16:00) correctly, this means that the resonant absorption frequency of for example a blue item is the same frequency (blue color) that is irradiated from the item into our eyes. Does that mean that a black item has no resonant absorption frequency in the visible light spectrum (because all visible light is transformed into heat) and a white item's resonant absorption frequencies span over the entire visible spectrum? This should also mean that a red item would heat up a bit more than the same item in blue (because the red item absorbes blue color, which is more energetic). Or can items have more resonant absorption frequencies, which combined make its color? Thanks.

  • @upscprep6215
    @upscprep6215 4 роки тому

    In Lockdown ....rather to watch web series .... It's better to watch Sir's lecture. ☺️

  • @moonlightblue3204
    @moonlightblue3204 Рік тому

    nice and clear tutorial, but just i am concerned about 51:16 , isnt that max I should occur at w_max which is slightly leftward instead of w_0 like in amplitude graph?

  • @mhamadhantro9818
    @mhamadhantro9818 4 роки тому +1

    First i want to Thank you for your wonderful lectures..
    Now i have a question, notice the graph around 35:45, you've said that the average gained power is maximum at w=w0, isn't weird because the maximum amplitude is seen at wmax below w0, so one can suspect that the maximum average Power will be on wmax not w0 (Intuitively speaking, i didn't check the math).

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  4 роки тому +1

      yes it is perhaps not intuitive. But amplitude alone does not determine the average power. Follow the math if I show it.

  • @anupammondal9511
    @anupammondal9511 5 років тому +1

    ok let us consider that damping is very very low for a pendulam . In that condition in resonence the amplitude should be infinity theoritically . but actually what happens in the case ?

  • @advarbindkumar5791
    @advarbindkumar5791 2 місяці тому +1

    Sir which books were you following at that time?

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  2 місяці тому

      8.01
      Physics
      Hans C. Ohanian
      Physics
      Volume 1
      2nd edition
      W.W. Norton & Company
      ISBN 0-393-95748-9
      8.02
      Physics for Scientists & Engineers by Douglas C. Giancoli.
      Prentice Hall
      Third Edition
      ISBN 0-13-021517-18
      8.03
      Vibrations and Waves by
      Anthony French
      CRC Press
      ISBN 9780748744473
      8.03
      Electromagnetic Vibrations, Waves and Radiation
      by Bekefi and Barrett.
      The MIT Press
      ISBN 0-262-52047-8

  • @TheGameDuke
    @TheGameDuke 6 років тому

    11:43 Mr.Lewin ,you write that at t=0 , velocity = 0 . That means that the starting point of oscillation is at the X = amplitude . But you write that X=0 at this point which means that X(max) = 0 , right ?
    Greetings from Greece

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  6 років тому +1

      I watched it 11:35-12:00 and everything I said and did is correct. I cannot add to the clarity of this lecture.

  • @svaditya2896
    @svaditya2896 4 роки тому

    in an electrical oscillation system(lcr circuit is given voltage v as a function of time doing exactly function of external force in a mecanical system

  • @l.-.l5451
    @l.-.l5451 3 роки тому

    Shouldn't P(max) be at a point lesser than w0?
    I am talking about what you have explained 35:33 minutes into the video...

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  3 роки тому

      no, what I have is correct - listen to what I said at 35:21

    • @l.-.l5451
      @l.-.l5451 3 роки тому

      @@lecturesbywalterlewin.they9259 Thank you for your reply, but just to clarify you had mentioned before that Amplitude is maximum at a freq lesser than its resonant frequency. So should the power also be the same ?

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  3 роки тому

      at what time did I mention that? You must be cofused with another situation. I am very very specific at 35:21 that P_max is at ωo. Ofcoz I recall tha I cover in 8.03 that a maximum *(maybe not P)* is reached NOT simultanepously with ωo. I do not have the time now to go over the lecture and to also go over others. That may take me more than 1 hr. If I state at 35:21 very loud abd clearly that Pmax MUST be at ωo. Then you better beieve that.

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  3 роки тому

      I recall that in one of my 8.03 lectures I stress that the max amplitude is NOT at omega-zero and I made a plot on the blackboard *which clealy shows that.* I do not have the time to find out in which lecture that is. I gave these lectures 17 years ago. If I said at 35:22 that P_max occurs precisely at omega_zero then that is 100% correct.

    • @l.-.l5451
      @l.-.l5451 3 роки тому

      Thanks a lot for the clarification...

  • @tushardey7653
    @tushardey7653 4 роки тому

    Thanks a lot sir......love from India

  • @Dra60oN
    @Dra60oN 9 років тому +1

    When you say that the amplitude goes down by factor of e it means that one time constant of the circuit has passed?

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  9 років тому

      +Ivan Antunović how many minutes into the lecture?

    • @Dra60oN
      @Dra60oN 9 років тому

      +Lectures by Walter Lewin. They will make you ♥ Physics. 56:56

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  9 років тому

      +Ivan Antunović The 1/e decay time here is the time for the amplitude of the transient oscillations to go down by a factor of e.

  • @familiapaudarco
    @familiapaudarco 4 роки тому

    hello professor walter lewin, i'm brazilian, and in this video subtitle is not activated. unfortunately I can’t understand what you’re talking about, can you provide the caption in this video? thank you.

  • @gabe-d8u
    @gabe-d8u 3 місяці тому

    hello sir, can you tell me where I can find the problem sets for this course? Also, thank you so much for explaining the general solution of a differential equation! At Politehnica, we were only taugh how to solve these, not what they actually mean

  • @denishtrivedi3071
    @denishtrivedi3071 5 років тому

    When you took the time derivative of energy for power ,why wasnt product rule applied because of Force here is oscillatory cos(wt) i.e. a function of time ,why? 23:00

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  5 років тому

      at 23:00 I calculate dx/dt=v thus no product rule

    • @denishtrivedi3071
      @denishtrivedi3071 5 років тому

      @@lecturesbywalterlewin.they9259 But power is the total derivative of d/dt(Fdx) where the time dependance of Force should kick in 😅

    • @denishtrivedi3071
      @denishtrivedi3071 5 років тому

      @@lecturesbywalterlewin.they9259 This should be the special case where Force is time independent and moves out of differential giving Fdx/dt=Fv

  • @TejasKd221B
    @TejasKd221B 6 років тому +1

    When you said Dark Bands were discovered in "18 oh 2", I thought 18.02! :P
    Nice lecture btw! :D

  • @ezzelgaby2246
    @ezzelgaby2246 7 років тому

    21:45 When you differentiate the work with respect to time how is it that it became the force times the velocity when the force is also a function in time. Shouldn't it be df/dt times x + dx/dt times f (product rule for differentiating)?

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  7 років тому +1

      dW=F.dx Thus dW/dt = F.dx/dt
      If W were F.x then dW/dt=x*dF/dt + F*dx/dt

    • @ezzelgaby2246
      @ezzelgaby2246 7 років тому

      Why then do we consider a constant force in our definition of work? Why is this a better definition of work than considering the change in F?

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  7 років тому +1

      take a mass m. Nail it to the floor so that it cannot move. Push on that mass with force F, change F as much as you want to, NO work is done as the object never moved.

  • @akashsunil7464
    @akashsunil7464 Рік тому

    Damn this was a huge lecture and we expllored a diverse amount of topics like bro we went from merchanical systems to rlc circuits tuning forks and atomic spectra WOAH THATS A LOT (and how on earth did we even end up there )

  • @padraiggluck2980
    @padraiggluck2980 Рік тому

    Prof. Lewin refers to the late A.P. French. R.I.P., died in 2017 at the age of 96.

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  Рік тому +1

      8.01
      Physics
      Hans C. Ohanian
      Physics
      Volume 1
      2nd edition
      W.W. Norton & Company
      ISBN 0-393-95748-9
      8.02
      Physics for Scientists & Engineers by Douglas C. Giancoli.
      Prentice Hall
      Third Edition
      ISBN 0-13-021517-18
      8.03
      Vibrations and Waves by
      Anthony French
      CRC Press
      ISBN 9780748744473
      8.03
      Electromagnetic Vibrations, Waves and Radiation
      by Bekefi and Barrett.
      The MIT Press
      ISBN 0-262-52047-8

  • @200katzen
    @200katzen 2 роки тому

    Hello Dr. Lewin! Thank you for your amazing lectures, while I have a problem: Shouldn't the I's in the differential equation at 47:00 be q's? I would really appreciate it if you reply my question. Wish you happiness and health!
    With all due respect,
    Charles

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  2 роки тому

      what I have is correct. L=dI/dt etc etc

    • @200katzen
      @200katzen 2 роки тому

      @@lecturesbywalterlewin.they9259 But I=dq/dt so shouldn't it be q" instead of I", etc (what's I" lol)

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  2 роки тому

      @@200katzen yes but then q' ' ' would replace I ' ' would that be an improvent?

    • @200katzen
      @200katzen 2 роки тому

      @@lecturesbywalterlewin.they9259 OK I get it. My mistake. Thank you!

  • @rawadabiorm6298
    @rawadabiorm6298 5 років тому

    Very nice, thank you so much. I have a question if you please, it is not related to this topic. The question is when we are driving a manual car, the consumption of the fuel is greater at the first gear or the last gear? or in another way at low speed (first gear) or high speed (fourth or fifth gear...)? I asked a lot of teachers they don't give me a convincing answer. Thanks for you in advanced.

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  5 років тому

      question unclear

    • @rawadabiorm6298
      @rawadabiorm6298 5 років тому

      @@lecturesbywalterlewin.they9259 The consumption of fuel in the car is greater at high speed or low speed.

    • @stargazer7644
      @stargazer7644 3 роки тому

      Max fuel consumption happens at max power output. This happens at a particular engine speed, not a particular gear ratio. You can hit this point in any gear, but max load generally happens in higher gears in a car due to higher wind resistance. But the same thing could happen a lower gear if climbing a hill or pulling a big load.

  • @giplochon
    @giplochon 6 років тому

    Hi Professor,
    Concerning the damping of RLC circuits, I know mathematics say gamma = R/L, but is there an intuitive physicist thought that can explain why the capacitance does not show up in that equation and only the self-inductance of the circuit? Aren't they both reactances?
    Thanks,
    Xavier

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  6 років тому +1

      how many minutes into the video?

    • @giplochon
      @giplochon 6 років тому

      +Lectures by Walter Lewin. They will make you ♥ Physics. 56:28, but I think it is always the case for such a RLC circuit.

  • @federicogrijalba5548
    @federicogrijalba5548 4 роки тому

    Hi Prof. Sorry for bothering. I believe the links for the assignments and solutions are down. Can you please check them?
    Thank you very much

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  4 роки тому

      Assignments
      #1
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/CB3AA53D-1FB1-474C-B6D6-FF8536D4E6B0/0/ps1c.pdf
      #1 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/FFE1D9E2-DBF3-4CD8-8B1B-F73E17843DBC/0/sol1b.pdf
      #2
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/3A4ED21F-1A64-46D7-AAF9-F21700012D8D/0/sol2b.pdf
      #2 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/3A4ED21F-1A64-46D7-AAF9-F21700012D8D/0/sol2b.pdf
      #3
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/3A4ED21F-1A64-46D7-AAF9-F21700012D8D/0/sol2b.pdf
      #3 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/E4E42DD6-236B-4385-9271-8F03167D774B/0/soln31.pdf
      #4
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/58A9CBEC-8518-4600-BEC5-AEA7DF43E43B/0/ps4a.pdf
      #4 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/F7F1D886-80D4-442F-BDB4-05EB76F11FFB/0/sol4a.pdf
      #5
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/CF82C53A-374F-4120-92F6-7E1E14DAE6B8/0/ps5d.pdf
      #5 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/24798BA8-FB96-46BA-BC5B-5391D4162CB7/0/sol5b.pdf
      #6
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/D234211F-B8AD-42E5-8BE1-D9EF21960490/0/ps6a.pdf
      #6 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/459E874D-053D-4D7B-8075-20EECCC3416D/0/sol6b.pdf
      #7
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/AD1A6279-469E-4C29-87B4-ADECB2BA1482/0/ps7a.pdf
      #7 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/A433C9FC-1046-4E75-A4B1-A9BE51064AEA/0/soln7.pdf
      #8
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/0007078F-D334-4208-BE36-4E10CC4DED22/0/ps8.pdf
      #8 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/88F3393A-0CAD-42B3-81FC-055761FD05C1/0/soln8_f05.pdf
      #9
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/54C462AF-0F08-4D62-AAF1-22EAA2D6F3FB/0/ps9.pdf
      #9 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/51E022E4-B884-4674-AD39-B6F5F34AC3D0/0/sol9.pdf
      #10
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/817F5BE5-C0EB-40A2-A4F3-446DD5B2E23F/0/ps10a.pdf
      #10 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/894CB5C8-10F1-497E-883D-9B28C9CE9C2E/0/soln10.pdf
      #11
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/903D9B4B-008D-4B16-B18D-BCEA9FF5A7C6/0/ps11a.pdf
      #11 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/40060650-3616-438F-A9D1-F85D92C648C0/0/sol11a.pdf

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  4 роки тому

      Lecture Notes
      #6 Driven Coupled Oscillators
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/AD3B3844-7CA8-4425-9901-691ADA7F3F47/0/lec6.pdf
      #6 Analysis of Triple Pendulum
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/16640F50-CD5F-44A1-81C9-D7F701F816B4/0/trip.pdf
      #17 Resonances in Sound Cavity
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/104FBB76-55B2-447E-8CB0-C1CDABED495E/0/res_sweep500_sec.pdf
      #18 Fresnel Equations
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/25F09082-3BF8-4A58-9F3D-1FB2AFDBD074/0/fresnel.pdf
      ------------------------------------------------
      EXAMS
      #1
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/73C7AAFD-A6E0-4D8E-A965-1199CA5A8006/0/ex1.pdf
      #1 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/E27BEF7A-C589-425C-A63B-8BEE8FC92318/0/ex1_sol.pdf
      #2
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/186394EB-B27D-49F2-B616-AB45A478CC0A/0/exam2.pdf
      #2 sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/287E964F-473B-4919-9EF2-5C510A0EBC92/0/sol1_ex2.pdf
      Final
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/B0168BDE-97F0-4948-B85B-065BAC194992/0/final.pdf
      Final sol
      mit.ucu.ac.ug/NR/rdonlyres/Physics/8-03Fall-2004/990A9643-64D5-4BF6-9085-B09A587DD26E/0/soln_final.pdf

    • @federicogrijalba5548
      @federicogrijalba5548 4 роки тому

      @@lecturesbywalterlewin.they9259 Thanks :)

  • @prakharbhalla9461
    @prakharbhalla9461 5 років тому

    Sir at 47:00 the amplitude of I is same as for spring case after replacing numerator with V zero omega/L. But tan delta is inverse of spring case with a negative sign i.e., (omega squared minus omega zero squared)/ omega delta. Is it correct?

  • @88coe
    @88coe 6 років тому

    Ι have a question regarding the derivation of the power formula.
    We have : dW = F.dx --> dW/dt = F. (dx/dt) = F.u
    why don't we also differentiate the force (as it scales with cos(ωt) ) but only dx?
    Thank you for another fantastic learning experience.

  • @badrmahmoud4437
    @badrmahmoud4437 4 роки тому

    Why did you ignore that the force is time dependant when you differentiated the work to get the power?
    thanks in advance

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  4 роки тому +1

      how many minutes into the lecture

    • @badrmahmoud4437
      @badrmahmoud4437 4 роки тому

      @@lecturesbywalterlewin.they9259 23

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  4 роки тому +1

      I watched at time 23. the force is time dependent.
      WAtch it again and pay more attention.

    • @badrmahmoud4437
      @badrmahmoud4437 4 роки тому

      @@lecturesbywalterlewin.they9259 P=dw/dt=d(F.x)/dt then you treated F as it's a constant and then you wrote P=F.dx/dt=Fv, Shouldn't F been differentiated too?
      and thanks for replying.

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  4 роки тому +1

      @@badrmahmoud4437 listen more carefully to what I said and wrote. I cannot add to my clarity - sorry

  • @yush742
    @yush742 3 роки тому

    What is the name of the book? Refered in the video

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  3 роки тому +1

      8.03
      Vibrations and Waves by
      Anthony French
      CRC Press
      ISBN 9780748744473
      8.03
      Electromagnetic Vibrations, Waves and Radiation
      by Bekefi and Barrett.
      The MIT Press
      ISBN 0-262-52047-8

  • @canned_heat1444
    @canned_heat1444 6 років тому

    In the rlc circuit when you set w->w0 and both self inductance and capacitance cancel, why does the voltage from the power supply go away? Does it have anything to do with it going to zero when w->w0? Thanks

  • @mehdibelhous7174
    @mehdibelhous7174 7 років тому

    How did you average sin(wt)cos(wt) at 26:00 ??

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  7 років тому +1

      use google - trigonometry

    • @JensenPlaysMC
      @JensenPlaysMC 3 роки тому

      personally I'd integrate from 0 to 2pi. then divide by 2pi to find the average. ( area / width = average height)

  • @deveshvaish8182
    @deveshvaish8182 4 роки тому

    Sir, at around 31:25 you said that the gamma is in the denominator so whole thing would turn to zero but numerator also contains gamma..wouldn't it result to infinity at very high values of gamma..though I agree with the intuition.
    Also thanks for such great lectures🙂

  • @ShivanshTrisal
    @ShivanshTrisal 4 роки тому

    Professor!! how can i get mini quiz of these lectures???

  • @sohamfalls2001
    @sohamfalls2001 4 роки тому

    We have : dW = F.dx --> dW/dt = F. (dx/dt) = F.u
    why don't we also differentiate the force (as it is also time-dependent ) but only dx?

    • @bilalhussein9730
      @bilalhussein9730 4 роки тому

      It's shorthand for using the fundamental theorem of calculus and reparameterization.
      Here's a derivation you'll hopefully understand better:
      W = int F.dr = int F.v dt' where we changed variables from position to time by using the velocity. But P= dW/dt so by the fundamental theorem of calculus P= F.v.

  • @emorell96
    @emorell96 9 років тому

    Do you happen to have the mini-quizes of these lectures? Thank you.

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  9 років тому

      +Enrique Morell I probably have them with my8.03 lecture notes, but not on line.

    • @emorell96
      @emorell96 9 років тому +1

      +Lectures by Walter Lewin. They will make you ♥ Physics. Would you be so kind as to upload them whenever you have some free time please? Btw, happy new year Professor.

  • @uditasharma6145
    @uditasharma6145 Рік тому

    can someone please clarify what is meant by adjustable constants?

  • @ilovephysics350
    @ilovephysics350 5 років тому

    In the Assignment-Solution is a y missing. Over equation (7) in the left equation after the omega zero squared🙄

  • @gokulchandran5586
    @gokulchandran5586 5 років тому

    sir, is there lecture no.3?....it is not in the list....

  • @rupeshknn
    @rupeshknn 6 років тому

    Sir,
    What happens to the transient term in an undamped system? Does both frequencies continue to exist in superposition?

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  6 років тому

      question unclear

    • @rupeshknn
      @rupeshknn 6 років тому

      It is said in the lecture 9:35 that in forced damped oscillations the transient response dies away after some time due to damping. But if there is no damping, what happens to the transient response.

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  6 років тому +1

      there is ALWAYS damping - it's part of mother nature

    • @rupeshknn
      @rupeshknn 6 років тому

      Sure sir! I was just wondering as to what could the sollution be.

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  6 років тому +1

      solve the diff eqs without the damping.

  • @physl2787
    @physl2787 5 років тому

    Sir if there is no damping of oscillator than the tranisent solution do not come

  • @abdelfettahbirouk9762
    @abdelfettahbirouk9762 8 років тому +1

    Thank you so much

  • @godisgood2482
    @godisgood2482 4 роки тому

    How u write sin(wt-greek symbol)=sin wt cos greek symbol-coswt sin greek symbol ??? How u write that

  • @nybble
    @nybble 5 років тому +3

    Your brooch looks like a hard drive platter in this video!

  • @shrikantguddalli8367
    @shrikantguddalli8367 3 роки тому +1

    Whenever I have an exam, I study your lecture and I have done well in exam.

  • @subhabrataghosh3565
    @subhabrataghosh3565 7 років тому +4

    don't worry you are still young in physics.:):)

  • @BroadeningHorizonsos
    @BroadeningHorizonsos 8 років тому

    do fluids have a fix frequency???????????

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  8 років тому +1

      question unclear

    • @BroadeningHorizonsos
      @BroadeningHorizonsos 8 років тому

      whenever we vibrate a liquid, waves are formed in it ...so is there a resonating frequency in which the waves will go high??

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  8 років тому

      transverse waves
      resonance frequencies depend on propagation speed of the waves and that depends of the density of the liquid.

    • @BroadeningHorizonsos
      @BroadeningHorizonsos 8 років тому

      I am still very unclear
      the sea waves which we see are due to some resonance???

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  8 років тому

      sea waves as you see them are driven by the wind. That's not a resonance.
      If you put water in a pan and you shake the pan, then you can excite resonance freq

  • @gauravchaturvedi4321
    @gauravchaturvedi4321 4 роки тому +2

    Wish I was in dat cls 🔥😎

  • @_N0_0ne
    @_N0_0ne 2 роки тому

    Thank you kindly ✍️

  • @scott3682
    @scott3682 5 років тому

    Do we know the frequency of the earth?

    • @lecturesbywalterlewin.they9259
      @lecturesbywalterlewin.they9259  5 років тому

      question unlcear

    • @scott3682
      @scott3682 5 років тому

      @@lecturesbywalterlewin.they9259 What is the frequency that the sun and other planets would receive from the earth? Inside we have the Schumann resonances. Isn't there a baseline resonance or is it constantly changing like with the Schumann?

  • @terencewinters2154
    @terencewinters2154 3 роки тому

    The upstairs and the downstairs and the side to side stairs . Like an escher artwork. You're omega is not their omega.

  • @jefferyleath
    @jefferyleath Рік тому

    Like I said I love to check that out I think exactly what I'm going to do that it's a brilliant I'm going to do it

  • @EPICMOVIES-2024
    @EPICMOVIES-2024 3 роки тому

    Only legends visit this page everyday to understand how mother nature behaves 🌊

  • @ManojKumar-cj7oj
    @ManojKumar-cj7oj 4 роки тому

    :)
    Thanks professor

  • @habibusaidu9393
    @habibusaidu9393 7 років тому

    i or we really appretiate your lecture and efford made when deliverinf the lecture, but sir i have a confusion area regards to your lecture, though i love your lecture most, your calculation is confusing me because you really go deeply when calculating a problem, not really well arranged as i'm especting

  • @sivamass7518
    @sivamass7518 4 роки тому

    Ok sir

  • @aniketjhariya3002
    @aniketjhariya3002 3 роки тому

    This gave me depression.

  • @deveshvaish8182
    @deveshvaish8182 4 роки тому

    Sir, at around 31:25 you said that the gamma is in the denominator so whole thing would turn to zero but numerator also contains gamma..wouldn't it result to infinity at very high values of gamma..though I agree with the intuition.
    Also thanks for such great lectures🙂