12.1 Pulley Problems

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  • เผยแพร่เมื่อ 1 มิ.ย. 2017
  • MIT 8.01 Classical Mechanics, Fall 2016
    View the complete course: ocw.mit.edu/8-01F16
    Instructor: Dr. Peter Dourmashkin
    License: Creative Commons BY-NC-SA
    More information at ocw.mit.edu/terms
    More courses at ocw.mit.edu

ความคิดเห็น • 39

  • @peeyushawasthi9843
    @peeyushawasthi9843 5 ปีที่แล้ว +30

    3:21 - "Our Rope is not slipping"
    3:25 - "Rope is actually just slipping"

  • @marcochimio
    @marcochimio 3 ปีที่แล้ว +4

    I got everything, except one part: How can mass 2 have a non-zero acceleration, but the free-moving pulley it's directly attached to, pulley B, has NO acceleration?

  • @blazenee
    @blazenee ปีที่แล้ว

    Thank you very much, I must say this level of understanding is just superb

  • @tenma5220
    @tenma5220 6 ปีที่แล้ว +65

    He knows how to write backwards very well :/

    • @scientist30
      @scientist30 5 ปีที่แล้ว +14

      He's not writing backward. Computer program flipping it!!

    • @harshawanasekara5425
      @harshawanasekara5425 5 ปีที่แล้ว +1

      Lol

    • @itsnoname797
      @itsnoname797 5 ปีที่แล้ว +1

      technology on attack..HELP!

    • @aleksandramichalak7826
      @aleksandramichalak7826 4 ปีที่แล้ว +2

      It's called a learning board. No computer flipping involved 😊

    • @TomSwiftful
      @TomSwiftful 4 ปีที่แล้ว +11

      ​@@aleksandramichalak7826 Except his shirt pocket is on the wrong side (for men's shirts), his shirt buttons are reversed from normal (should be left over right), and it's statistically unlikely that he and every other instructor who uses this technique are left handed. The image is almost certainly being mirrored (flipped) in post-production.

  • @rhemalogos7980
    @rhemalogos7980 4 ปีที่แล้ว +4

    This has been such a good explanation. But now i have just a little problem with pulley B. We assume that the pulleys are approximately massless and when we get that T3=2T does it mean that the pulley is stationary or that it is moving with constant velocity because i think it can not be stationary given the fact that m2 is pulling it downwards and if it is moving then it is accelerating with thesame acceleration as m2 but will be in disagreement with the equation established.I kind of understand here that it is the mass been approximated to zero that sets all this but what is physical interpretation of the fact that we approximate the mass to be zero and it leads to forces acting on it being balanced So actually I am lost at that point someone please help me with an explanation

    • @ryanschilling7031
      @ryanschilling7031 8 หลายเดือนก่อน +1

      I'm sure you don't care about it 3 years later, but this is how I understand it. First, think of the pulley having some mass, m. In the case of the tensions on one of the pulleys, so for pulley B, 2*T - T3 would be the net force on the pulley, and Net force = ma, so 2*T - T3 = ma. If you solved for T, you would get T = (ma - T3)/2. Maybe if you look at this equation, you can see that no matter the acceleration, as m approaches zero, T will approach (T3)/2, so even if there is acceleration, the forces have to balance out.

  • @renaqazi9428
    @renaqazi9428 6 ปีที่แล้ว +2

    Amazing explanation...

  • @medentrance1142
    @medentrance1142 3 ปีที่แล้ว +1

    Great sir.......awesome.........

  • @BennettAustin7
    @BennettAustin7 4 ปีที่แล้ว

    Gracias

  • @StubProductions
    @StubProductions 3 ปีที่แล้ว +5

    This is the worlds most complicated explanation on calculating pulleys! Lol! This is the difference between engineering and science.

  • @amiothenes
    @amiothenes 3 ปีที่แล้ว +3

    you are making this way more complicated than it needs to be, just watch van Biezen

  • @keeferlin275
    @keeferlin275 4 ปีที่แล้ว

    Mind BLOWN

  • @navindupremasiri9382
    @navindupremasiri9382 3 ปีที่แล้ว +1

    Thank you sir

  • @pranjalverma3501
    @pranjalverma3501 6 ปีที่แล้ว +1

    nice video.

  • @shiva2415
    @shiva2415 5 ปีที่แล้ว +5

    Pulley B is not fixed it is coming downward so we cannot write it as T3-2T=0

    • @neoneon6076
      @neoneon6076 5 ปีที่แล้ว +6

      It is a massless pulley so m_B = 0, so m_B*a = 0.

    • @ReanPhysicsMath3121
      @ReanPhysicsMath3121 4 ปีที่แล้ว

      @@neoneon6076 What about the equation of m1? Since pulley B and block 2 are pulling downward, the block 1 will move upward. As we assume that taking down is positive, the acceleration a1 of m1 would be negative but not positive. He wrote it as positive. Is it wrong? Please, answer. Thank You.

  • @anushreedey5448
    @anushreedey5448 6 ปีที่แล้ว

    nice one .helping one.....

  • @soumyajitmaiti752
    @soumyajitmaiti752 ปีที่แล้ว

    How is he able to write in the reflected manner so easily..??

    • @kaidendickson1429
      @kaidendickson1429 ปีที่แล้ว

      the video is flipped. Notice he's writing with his left hand when it's more than likely he's right handed

  • @alchemy1
    @alchemy1 5 ปีที่แล้ว +2

    Some of them pulleys are pretty dog gone heavy. It is nice to just assume things, you know it is so much easier. Hey lets all go home now and have a beer.

  • @prasathk1856
    @prasathk1856 4 ปีที่แล้ว +1

    Board is an abscurd.

  • @pam9451
    @pam9451 5 ปีที่แล้ว +1

    tnx xx

  • @sureshsaxena6013
    @sureshsaxena6013 6 ปีที่แล้ว +2

    Plz in hindi

    • @classicsalted
      @classicsalted 4 ปีที่แล้ว +9

      Haha fuck you!

    • @dvnsyaswanth9936
      @dvnsyaswanth9936 3 ปีที่แล้ว +1

      you hindi people can learn from a channel called physics wallah

    • @bharadwajeddanapudi8507
      @bharadwajeddanapudi8507 ปีที่แล้ว

      bro every learning vid in hindi pisses me off