More on moment of inertia | Moments, torque, and angular momentum | Physics | Khan Academy

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  • Опубликовано: 27 ноя 2024

Комментарии • 122

  • @saifsayed5019
    @saifsayed5019 4 года назад +163

    I am an engineer having 7 years of work experience in Structural field and today's the day I actually got to know what Moment of Inertia literally means.

    • @gilbertwamichwe1190
      @gilbertwamichwe1190 3 года назад +11

      Welcome to the club

    • @adityagopinathan7791
      @adityagopinathan7791 3 года назад +22

      Then what your where doing last 7 years without knowing how to balance the weight equally

    • @hrn8935
      @hrn8935 2 года назад +6

      hol up

    • @YashodhanReddy
      @YashodhanReddy 2 года назад +9

      This is the reason our country is still "developing"
      These "dumb" people get jobs but don't know what they are dealing with..

    • @AdiPrimandaGinting
      @AdiPrimandaGinting 2 года назад +1

      I know you mean it as something funny, but it is actually something being dangerously very ironic

  • @cowgate
    @cowgate 4 года назад +1

    I'm quitting uni and just watching your videos now man. You cover this in no time but I'm sitting in 3 hour lectures? 🙄. Thank you!!

  • @Boleniana
    @Boleniana 7 лет назад +25

    This is really useful, thanks! I was having a hard time understanding what exactly this was, then someone in upper year physics recommended this.
    Also, thanks for having closed captioning. I'm watching this on a library computer, and you can't easily get volume with that.

  • @trevor7097
    @trevor7097 8 лет назад +89

    "If you don't know Calculus that would just look like witchcraft to you."
    I don't know why anyone would need a better reason to listen to these lectures. I laughed audibly enough for my neighbors to be concerned about my well-being. 10/10 would play on loop.

    • @rockyk6805
      @rockyk6805 5 лет назад +3

      ahhahahahhah damn ur comment made me laugh a little too hard too

    • @nrgaming5849
      @nrgaming5849 4 года назад

      Trevor loop means

    • @thetaiman5351
      @thetaiman5351 3 года назад +1

      Had the same reaction and went to look through the comments to feel validated.
      now I am.

  • @zafrizulfi
    @zafrizulfi 5 лет назад +75

    My professor has a Ph.D., but still, he didn't explain like this. He has 3 hours per week to teach.

    • @Born2Losenot2win
      @Born2Losenot2win 4 года назад +7

      Hahaha same, welcome to the bigboys study hall

    • @mrpee2482
      @mrpee2482 4 года назад

      Okay ... So what ?

    • @Born2Losenot2win
      @Born2Losenot2win 4 года назад +7

      MR Pee they are not meeting up with the standards even though they are getting payed by the standards,
      Basically the tutors on RUclips deserve more than this and people who don’t do their job right don’t

    • @mrpee2482
      @mrpee2482 4 года назад

      @@Born2Losenot2win Okay

    • @bradvincent2586
      @bradvincent2586 4 года назад +6

      @@mrpee2482 so it is absurdly pathetic that countless college professors are incapable of communicating basic principles in their field. Maybe 10% of my professors have been reasonably good

  • @soramin1599
    @soramin1599 4 года назад +5

    u just made my life 10times easier. i wish u were my professor in physics

  • @larrynmcmahan9536
    @larrynmcmahan9536 5 лет назад +7

    I saw this video, and when I saw the collection of point masses, I said "Hey! This is just a Riemann sum," I can figure by just integrating all the "point masses" together. I was able to verify the equation of I for a sphere this way.

  • @ankitaroy759
    @ankitaroy759 7 лет назад +10

    Thank you!!!! , khan academy has always been a life saver for me.

  • @nandha0150
    @nandha0150 8 лет назад +18

    Excellent explanation. Thanks
    Gratitude from India :)

  • @ProlificPianist
    @ProlificPianist 3 года назад +1

    This helps so much. My teacher & book have been throwing different values of inertia around with zero explanation or what the heck the significance of a point mass is. While I still need some more work with it, this has cleared up so much of the mystery as to why 1/2, 1/3, 1/12 and so on.

  • @vishnuprasadha4449
    @vishnuprasadha4449 7 лет назад +33

    Dave you just saved a man's CGPA

  • @bantehromarick5053
    @bantehromarick5053 Год назад +4

    Thank you so very much. Ur teaching method is so dynamic and clear. Please don't stop uploading. 🙏🙏 Great video

  • @Slime5276
    @Slime5276 7 лет назад +5

    Very well explained! Thank you so much.

  • @FLstudioProjectfiles
    @FLstudioProjectfiles 6 лет назад

    I am preparing for indian embassy examination from you channel😃😃 I appreciate your help.
    Thank you very much.😃😃

  • @aliciapang9006
    @aliciapang9006 4 года назад +23

    I am about to literally drop out of my college and major in interpretive dancing or something IDK.

  • @vj9995
    @vj9995 7 лет назад +184

    thank you my ap physics teacher is useless

    • @Nik-wo7hk
      @Nik-wo7hk 7 лет назад +4

      vmar same my teacher cant solve some of the easy problems

    • @ilmihaqim3186
      @ilmihaqim3186 6 лет назад +21

      well, my teacher is smart genius, the problem is he thinks everyone in class is a genius. SO, we can't catch up to his pace...

    • @sophiem7770
      @sophiem7770 5 лет назад +4

      ilmi haqim abdul nasir lord I know the feeling- everyone in my class failed a test and he said Aw Damn Sucks To Suck and moved onto the next unit.

    • @666-e9w8e
      @666-e9w8e 5 лет назад +2

      2 years later this video saves another student's life :)

    • @chansam4917
      @chansam4917 4 года назад

      Well, my Math teacher used 3 months to teach all the thing that we are supposed to learn in this whole year, its like one chapter one lesson. And everyone failed the exam beside those insanely smart students. Than my Math teacher be like, I know you guys got this, all of you are smart, just pay more attention so you can pass. -_-

  • @albertwood8836
    @albertwood8836 3 года назад +1

    Great explanation! And I'm actually happy that you didn't do the calculus, so i can do it myself...

  • @alfanalarabi1137
    @alfanalarabi1137 7 лет назад +3

    this saved my life, ty

  • @marthalatorre2383
    @marthalatorre2383 2 года назад +5

    Excellent video, very good explanation. I have a question: what are the differences between the MIM and the Volume Moment of Inertia?

  • @sanidhyasharmaji3422
    @sanidhyasharmaji3422 Год назад

    You don't know what have you uploaded my dear you are God of physics for me from now❤❤❤❤❤❤❤❤❤❤❤❤❤❤

  • @Bobby14221234
    @Bobby14221234 6 лет назад +7

    Would be nice if you back up your lectures with calculations when you say inertia becomes 1/3 or 1/12 ..

  • @melodynamics9957
    @melodynamics9957 8 лет назад +2

    I like the way u teach! Clarified all my questions!! thanks :)

  • @SQUELCH-zj7il
    @SQUELCH-zj7il 5 лет назад

    Moment of inertia for a solid beam and hollow beam please!! There is nothing about this that is very helpful on youtube! Thanks..though i have a wee test on this on Monday

  • @speakingbooks3727
    @speakingbooks3727 4 года назад +1

    In this video they discuss about Mass moment of inertia, but didn't mention that.
    It should be mentioned that mass moment of inertia and area moment of inertia are different.

  • @galaxyfr3sh
    @galaxyfr3sh 7 лет назад +1

    Freshman in college trying to take physics- if you take the integral of the general equation of inertia, i could swear that you get I=(1/3)*mL^3 and when changing the axis of the rod, you should be able to use the same integrated formula but just divide L by the farthest points if the farthest points are equal on both ends

    • @groyt541
      @groyt541 6 лет назад +2

      You have to divide the mass by L in order to get that fraction of mass in each little slice you're adding up

  • @jackbrujali5372
    @jackbrujali5372 2 года назад

    Bro this is really helpful, thank you

  • @AbuSayed-xs5jn
    @AbuSayed-xs5jn 2 года назад

    Grateful explanation

  • @AtagherUsha
    @AtagherUsha 10 месяцев назад

    This is really amazing

  • @SHwao123
    @SHwao123 3 года назад

    It's been a great help to study kinetics.

  • @marufhasan2516
    @marufhasan2516 7 лет назад +1

    Great explanation to understand.... thank you... hope to get more...

  • @pixelrabbit261
    @pixelrabbit261 4 года назад

    I can't believe I' saying this, but could you point me in the direction of the calculus for this? Great video.

  • @renevega2
    @renevega2 7 лет назад +1

    Very helpful. Thank you.

  • @Zhujiayi7
    @Zhujiayi7 4 года назад

    thanks david

  • @SuningH
    @SuningH 2 года назад

    omg brilliant!!!!!

  • @faarisalam3900
    @faarisalam3900 5 лет назад

    You just saved my career! Thank you!

  • @alhabibahmed6440
    @alhabibahmed6440 2 года назад

    Thank you❤❤❤❤ so much ❤❤❤

  • @rainGod81
    @rainGod81 3 года назад

    Thank-you

  • @pappin7423
    @pappin7423 3 года назад

    great content, thanks alot

  • @ucontrol7858
    @ucontrol7858 2 года назад

    thank you .....what is the program you are using?

  • @kaleab27
    @kaleab27 4 года назад

    Thanks

  • @yjmsniper
    @yjmsniper 5 лет назад +4

    What about the second moment of inertia for deflecting a beam?

    • @carultch
      @carultch 3 года назад

      It is a misnomered term, that has nothing to do with inertia. A better name for it is "second moment of area". It is a concept that is analogous to the moment of inertia, except you replace differential mass in the integral, with differential area. It is a property that indicates the geometric stiffness of a cross section to support a bending load.

  • @gabewinter9406
    @gabewinter9406 2 года назад

    At first it seemed counterintuitive given torque/moment increases with distance, but imagine being spun on ice skates holding an object close to you or farther away.

  • @Mohammadalhashash
    @Mohammadalhashash 7 лет назад

    Nice explanation, thanks alot

  • @8cec
    @8cec 8 лет назад +3

    Please dont stop making these awesome videos !!! = ]

    • @walidzein1
      @walidzein1 8 лет назад

      i have a test on monday and i really need help ,do u have old physics test about the momentum angular momentum thank u

  • @alienproductions9679
    @alienproductions9679 2 года назад

    Just” learn calculus “ he says it so easily

  • @sonofquebec
    @sonofquebec 6 лет назад

    Thanks that was very helpfull !

  • @phylipeesposte8906
    @phylipeesposte8906 5 лет назад

    Thank you!!!

  • @hiexpressdoral7714
    @hiexpressdoral7714 5 лет назад +1

    Very helpful explanation and example. Great work!

  • @briarmahamd2767
    @briarmahamd2767 5 лет назад

    well done

  • @oximas-oe9vf
    @oximas-oe9vf 2 года назад

    what exactly are we taking the intergal of ?

  • @davisjohn-d6h
    @davisjohn-d6h 6 лет назад

    THANK YOU

  • @jordanwinslow978
    @jordanwinslow978 3 года назад

    what is that app? please

  • @jordankhadafi6416
    @jordankhadafi6416 6 лет назад

    tq

  • @splashtech7093
    @splashtech7093 2 года назад

    4:31 4:33 for

  • @CillianMurphy.
    @CillianMurphy. 8 лет назад

    Thanx sir

  • @nitingupta4k
    @nitingupta4k 5 лет назад

    what if the center of the mass is on the center of the rotation axis?should we take r =0

  • @harjassingh388
    @harjassingh388 Год назад

    How moment of inertia of axial fan can be calculated

  • @rinesaajdari8316
    @rinesaajdari8316 Год назад

    I am guessing that for the moment of Inertia for the cylinder you should have to take the integral of m*r² for dm. This should be 1/2m²r², why is the mass not to the second in your video?

  • @clemsmith2253
    @clemsmith2253 3 года назад

    What is inertia telling us. I have to find inertia in a wood beam and I end up with 1230 in cubed. What does that mean. That 1230 cubed of the wood beam is the minimum for it not to be overturned? but at what force?

    • @carultch
      @carultch 3 года назад +1

      Which "moment of inertia" are you talking about, because the term is used for two unrelated concepts? Moment of inertia as discussed in this video has the units kilograms-meter^2. The other kind of "moment of inertia" that should really be called "second moment of area" has the units meters^4 (or other distance units).
      Moment of inertia in this context, refers to the mass moment of inertia, which is a body's resistance to a change in state of rotational motion, that when multiplied by angular velocity gives angular momentum. It is a property of mass, shape, and distribution of mass.
      The other concept is the "area moment of inertia" or "second moment of area", which has *nothing to do with inertia*. This is purely a geometric property of a cross sectional shape, that indicates a structural shape's geometric stiffness against bending. The product of the second moment of area and Young's modulus, indicates how stiff a beam cross section is, against bending. This combination of factors relates bending moment to curvature of the beam. The reason it is called "area moment of inertia", despite having nothing to do with inertia, is that it has a lot of properties in common with the way we define mass moment of inertia. The essential difference is that we integrate relative to an infinitesimal area element dA, instead of relative to an infinitesimal mass element dm.

  • @maxyousofirahimi4555
    @maxyousofirahimi4555 7 месяцев назад

    why is the distance squared?

  • @wannabe-dev
    @wannabe-dev 2 года назад

    one question, you keep saying "if you do that integral", but what integral? i would actually know how to solve cause in my physics exam i dont have acess to any paper saying what the moment of inertia is for which case :/

  • @bluesapphire3615
    @bluesapphire3615 2 года назад

    But sir a point mass never rotates.
    Then how can we say that this point mass is rotating?

  • @mattasaikiran4812
    @mattasaikiran4812 5 лет назад

    Sir can you please explain me ,how moment of inertia of circular section of diameter D is {(πD^4)/64}

    • @ahusain03
      @ahusain03 4 года назад +1

      Actually in this video they discuss about Mass moment of inertia , {(pi.D^4)/64} is area moment of inertia.

    • @carultch
      @carultch 3 года назад

      That is a different kind of "moment of inertia", that really has *nothing to do with inertia*. A better name for it is "second moment of area". It is called "moment of inertia" because it has a lot of properties in common with mass moment of inertia, but the essential difference is that dm is replaced with dA. In other words, instead of using a differential mass element in the integral, we use a differential area element. A better name for it that is also used, is "second moment of area". An application of the second moment of area, is as a geometric measure of the stiffness of a beam cross section. This term, along with Young's Modulus, gives us the beam stiffness term.

  • @mohitdhadwal9840
    @mohitdhadwal9840 4 года назад

    Sir, moment of inertia for a disc or hollow cylinder is 1/2 mr^ but whole mass of the cylinder is distributed at a same distance that is r so why it is 1/2 mr^ not MR squr

  • @Igorinlondon
    @Igorinlondon 6 лет назад

    I would like to make a device to measure the moment of inertia of a bat or tennis racquet in an axis 10cm from the end of the handle. Can anyone help me? If necessary we can use arduino as devices to measure acceleration and angles.
    Thanks

  • @mohammada4523
    @mohammada4523 4 года назад

    I suggest you learn calculus

  • @amansourav9963
    @amansourav9963 6 лет назад

    why is I proportional to square of radius??

    • @carultch
      @carultch 3 года назад +1

      Because mass that is farther away from the axis of rotation contributes to its angular momentum in two separate factors. Angular momentum is r cross (m*v), where r is the distance from the axis of rotation. For a rigid body, the tangential velocity is proportional to radius as well, via the angular velocity. Both of these factors together, mean that the radius is squared in the moment of inertia definition.

  • @quantumaravinth
    @quantumaravinth 6 лет назад

    7 people who disliked are people who are the living testament of “madness”

  • @balkdermins1528
    @balkdermins1528 4 года назад

    what sofrtware and device do u use to make your vidz

  • @velcranell4860
    @velcranell4860 Год назад

    came here for the calculations of moment of inertia, disapointed!

  • @Kaori--
    @Kaori-- 3 года назад

    STEM PA MGA TNGAA AHAHHAHAHAH

  • @Hari-_-______-137
    @Hari-_-______-137 7 месяцев назад

    We are not dumb teacher's teaching makes us to feel that we are dumb

  • @varunkota1289
    @varunkota1289 6 лет назад

    isn't this supposed to be the other way? mass away from centre will make easier movement. for example we can close/open a door easily if force is applied away from the hinges

    • @khaledyasser8293
      @khaledyasser8293 6 лет назад +1

      Imagine trying to swing around a jug of milk tied to the end of a 10m string vs trying to rotate it when it's in your hands (both cases you're the axis of rotation)

    • @kkikkodan
      @kkikkodan 6 лет назад +1

      No . That's a completely different concept

  • @amenassefa
    @amenassefa 7 лет назад

    Awesome educational video and an even better joke... "If you don't know Calculus that would just look like witchcraft to you." hahaha

  • @M77-f2t
    @M77-f2t 4 года назад

    اووووف يلهندسة😫

  • @rockyavg7212
    @rockyavg7212 7 лет назад

    So what are the calculus topics you're required to cover in order to fully understand this lesson ?

    • @yogeshthakur6477
      @yogeshthakur6477 7 лет назад +1

      Bleeding Knife

    • @hrn8935
      @hrn8935 2 года назад

      You need to know the basics of differential and integeral calculus

  • @haxiom1589
    @haxiom1589 4 года назад +1

    Please add Bangla subtitles

  • @alext9067
    @alext9067 6 лет назад

    6:00 reducing radius by swinging a bat from the fat end? No. Tha reduces mass. Radius stays the same. Are we nuts here?

    • @nikhila6536
      @nikhila6536 6 лет назад

      The place where we hold is where the axis is located...now think
      ....

  • @busybee2771
    @busybee2771 6 лет назад

    Poor explanation 😏

  • @fathimafarah767
    @fathimafarah767 Год назад

    Thank you very much

  • @ryanthegooch5952
    @ryanthegooch5952 2 года назад

    Thanks

  • @mrlipton4571
    @mrlipton4571 2 года назад

    thank you so much

  • @zeinabmohamed1668
    @zeinabmohamed1668 2 года назад

    Think you

  • @harjassingh388
    @harjassingh388 Год назад

    How moment of inertia of axial fan can be calculated