Mass on a moving wedge

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  • เผยแพร่เมื่อ 26 ธ.ค. 2024
  • This video contains an excellent analysis to a rather hard problem: A mass resting on a wedge, which itself is free to slide on a horizontal plane. The problem is complicated because (a) there are two accelerations to keep track of, and (b) the kinematic constraint is not-so-easy to apply. Special attention to the careful use of a ghost force (which is fine!) in the accelerating frame.
    Quiz 1: webtest.boun.ed...
    Quiz 2: webtest.boun.ed...
    Quiz 3: webtest.boun.ed...
    Homework: webtest.boun.ed...
    ( The full playlist "Introductory Physics" is at
    • Introductory Physics )

ความคิดเห็น • 83

  • @NegativeAccelerate
    @NegativeAccelerate 4 ปีที่แล้ว +40

    This guy deserves all the compliments he’s getting. He rly helped me.

    • @LT-pp2vr
      @LT-pp2vr 4 ปีที่แล้ว +1

      you are right!!!!!!!

  • @RexGalilae
    @RexGalilae 8 ปีที่แล้ว +55

    Around 8000 engineers and physicists of the future have benefited from this great video!
    Great job and thanks a lot!!

  • @HarshRajAlwaysfree
    @HarshRajAlwaysfree 4 ปีที่แล้ว +6

    This so helpful I was stuck here for hours to figure out what was happening

  • @lakshyashukla2740
    @lakshyashukla2740 9 ปีที่แล้ว +6

    Helped a lot... You have generalized everything and that will help me to solve any problem.. Thanks a lot!!

    • @nj_149
      @nj_149 ปีที่แล้ว +1

      Hello bhaiya
      You gave JEE 8 years ago
      How is your lifestyle now?
      I am going to give it in 2025

  • @jeenius5882
    @jeenius5882 4 ปีที่แล้ว +13

    Sir be like, "Joh yeh tera torture hai ... woh mera warm-up hai"

    • @ParthTyagi
      @ParthTyagi 3 ปีที่แล้ว +3

      Mujhe lag hi raha tha apna koi a JEE/NEET aspirant mil hi jayega comment section me?

    • @mohitforimprovement
      @mohitforimprovement 2 ปีที่แล้ว +1

      @@ParthTyagi Hehe

  • @govindankandan4527
    @govindankandan4527 5 ปีที่แล้ว +3

    Sir, thank you so much. Your video was immensely helpful.

  • @santoshkesavan
    @santoshkesavan 7 ปีที่แล้ว +3

    Thank You very much explained a difficult problem very well.

  • @projectz935
    @projectz935 9 ปีที่แล้ว +4

    nice explanation....the problem can also be solved without using s pseudo force and that method gives more insight into the details of the problem....but anyways the ghost force approach (in non inertial frame of wedge) is easier and shorter....

  • @devmehi
    @devmehi 2 ปีที่แล้ว +2

    for such problem, is it possible to solve without using pseudo force (ghost force) by putting observer or frame of reference on ground.?

  • @mathOgenius
    @mathOgenius 4 ปีที่แล้ว +1

    can anybody please tell why acceleration of M is not negative because it's going backwards and other is positive..because it's going forward

    • @autumn_auburn
      @autumn_auburn 3 ปีที่แล้ว

      Because he already decided the direction of acceleration, so he only used the magnitudes of the acceleration in the problem.
      This is also the reason that value of R(Reaction force or Normal force) is a scalar(number) and not a vector in terms of i hat and j hat.
      Though the problem can be done with vector if you want signs. It won't be tidy though.

    • @mathOgenius
      @mathOgenius 3 ปีที่แล้ว

      @@autumn_auburn ohk thanks , It was an old comment , I have done it with vectors too, anyway thanks for explaining

    • @Messi-is-goat_10
      @Messi-is-goat_10 3 หลายเดือนก่อน

      ​@@mathOgeniusbro!! You're here?!!

  • @supriya1479
    @supriya1479 4 ปีที่แล้ว +1

    thank u sooo much sir u helped me a lot to solve many of the tough problems

  • @ParthTyagi
    @ParthTyagi 3 ปีที่แล้ว +1

    22:37-
    Sir, won't it be mg Sin^2 Q?
    Isn't the square on sin Q missing?
    Or maybe I am confused. Can someone please confirm?

    • @trivikram4962
      @trivikram4962 ปีที่แล้ว

      did u figure out what was wrong, am having the same issue

  • @laibajadoon7585
    @laibajadoon7585 4 ปีที่แล้ว

    Thnkiuu sir...it helps me alot to solve a problem...a great respect from...PAKISTAN

  • @ipsitasingh8339
    @ipsitasingh8339 6 ปีที่แล้ว +5

    What's the professor's name? His explanations are amazing! Thanks a lot for sharing this super useful and insightful content. :-)

    • @Besinnung
      @Besinnung 5 ปีที่แล้ว +3

      He is Alpar Sevgen from Bogazici University

  • @zukamot
    @zukamot 9 ปีที่แล้ว +1

    Thanks, I have spent many time with this problem, without make a real progress, I understand a little more tanks to you.

  • @jaycho3241
    @jaycho3241 6 ปีที่แล้ว +3

    This helped me a lot. Thanks :)

  • @RealEverythingComputers
    @RealEverythingComputers 17 วันที่ผ่านมา

    I had the same problem on a problem set, but I did it such that theta was the wedge's angle of inclination, and the "true course" of the mass sliding down would have a steeper angle, alpha. Is it necessary that alpha+theta=90 deg? It almost feels intuitively correct, but I'm having difficulty proving it... and I lost a few marks because of this, but I don't understand how it's wrong. Could you please clarify. Thx

  • @sayakghatak3218
    @sayakghatak3218 5 ปีที่แล้ว

    sir please dont feel hesitated while teaching , U are good enough !

  • @MrMariodesouza
    @MrMariodesouza 6 หลายเดือนก่อน

    It is possible expressing the motion of m in terms of the relative motion, but there is a lot of algebra.

  • @luigiluigi8297
    @luigiluigi8297 6 ปีที่แล้ว

    The best introductory physics course thanks

  • @ganeshab1996
    @ganeshab1996 12 วันที่ผ่านมา

    Sir why do we consider that acceleration of wedge is constant, when block is sliding over it. Can we prove it.

  • @carlkpsplucky5554
    @carlkpsplucky5554 4 ปีที่แล้ว

    I’m not a engineer or anything, just studying for the ASVAB. This should be a simple question for u guys. “If a wedge Is made longer relative to its height, how does the force increase?”

  • @chups3421
    @chups3421 3 ปีที่แล้ว

    Why do you not include the portion of the block 'm' (mg cos(Θ)) weight acting on the wedge 'M' in the reaction force(R)? Can sbd explain?

  • @SanjayKumar-dh1en
    @SanjayKumar-dh1en 5 ปีที่แล้ว

    Sir you are awesome ..... Keep posting even more videos...

  • @NegativeAccelerate
    @NegativeAccelerate 4 ปีที่แล้ว +1

    Go to 5:50 to skip warm up

  • @physicsexcellencegroup8945
    @physicsexcellencegroup8945 4 ปีที่แล้ว

    Awesome lecture sir, very well explain

  • @AnishKumar-qx5un
    @AnishKumar-qx5un 5 ปีที่แล้ว

    Hats off to you, sir!

  • @ayushijain8671
    @ayushijain8671 7 ปีที่แล้ว

    Thank you very very much.....You explained really well. May God Bless.....

  • @oxygen2671
    @oxygen2671 2 ปีที่แล้ว

    In 6:19 Why he didn’t make the force on the opposite direction ?

  • @abhinovenagarajan.s7237
    @abhinovenagarajan.s7237 6 ปีที่แล้ว +1

    How can we solve this question without using a pseudo force?

    • @shubhronildutta1563
      @shubhronildutta1563 4 ปีที่แล้ว +3

      We can use a Lagrangian to model the problem, and then use Euler Lagrange Equations to solve it without pseudo force.

  • @krishankantgupta2483
    @krishankantgupta2483 5 ปีที่แล้ว

    concept clearing video

  • @seanheeran5017
    @seanheeran5017 8 ปีที่แล้ว +4

    why is r not mgcos0?

    • @RexGalilae
      @RexGalilae 8 ปีที่แล้ว +1

      R should be equal to mgcos0+mAsin0 AFAIK.
      This is because R must counter both the force due to gravity AND the force due to the block's movement

    • @autumn_auburn
      @autumn_auburn 3 ปีที่แล้ว

      @@RexGalilae Yes, but that's like saying x + 1 = 11 - x instead of 2x + 1 = 11. You are right about the expression for R, but the acceleration A is written in terms of R.

    • @RexGalilae
      @RexGalilae 3 ปีที่แล้ว +1

      @@autumn_auburn
      My comment is over 4 years old, man. I was probably in my first year of college lmao
      Right now, I'm 1 year past graduation and in a line of work that has nothing to do with mechanics

    • @autumn_auburn
      @autumn_auburn 3 ปีที่แล้ว

      It is mgcos(θ) in an immovable wedge, do you know why? It is so because there is no motion of block perpendicular to the surface of wedge, so acceleration of block perpendicular to the surface is zero. Sine F=ma, and a=0 so F=0. That means force perpendicular to the surface of wedge is zero, and this means that the components of all forces perpendicular to surface should add up to zero or that opposite forces come out to be equal. Force on block away from wedge is R(the reaction force), and the component of gravity perpendicular to the surface of wedge is mgcos(θ), equating the two gives R = mgcos(θ).
      The same thing also applies in the problem with movable wedge, since there is no motion of block perpendicular to the surface of wedge(if you observe the block while standing on the wedge - that is in the reference frame of the wedge), you just equate the forces on the block going 'into' the wedge and 'out' of the wedge. But here in addition to the Reaction force(R) and gravity, we also have a pseudo force(due to us observing the block in an accelerating frame of reference). So just equate the forces and you will find that the reaction force(R) does not come out to be mgcos(θ).
      The interesting part is that in the expression for R, if you set M(mass of wedge) to be infinite, it says that R should then be mgcos(θ). This should be intuitive since an infinitely massive wedge is akin to a non movable wedge and so the expression for R just comes out to be the usual easy case that is R = mgcos(θ).

    • @autumn_auburn
      @autumn_auburn 3 ปีที่แล้ว

      @@RexGalilae lol I expected this. My comment might be useful for someone who stumbles on the same problem.

  • @mohammedsrivastava5917
    @mohammedsrivastava5917 4 ปีที่แล้ว

    Thank you very much Sir!

  • @RexGalilae
    @RexGalilae 8 ปีที่แล้ว

    when the wedge is pushed towards the right, why is the ghost force still acting to the right? shouldn't it be acting to the left now?

    • @HarshRajAlwaysfree
      @HarshRajAlwaysfree 7 ปีที่แล้ว

      Rex Galilae don't count me in though I'm a future scientist this video is a shit?!!!

  • @alluarjun3952
    @alluarjun3952 5 ปีที่แล้ว

    Sir ,you state the block is not jumping from the wedge,why it is so?,how will we decide this...if R makes wedge to move horizontal then why not it makes block jump from wedge and move parabolicaly..

    • @zhgshdbssss6536
      @zhgshdbssss6536 4 ปีที่แล้ว

      Allu Arjun i have the same question. I understand that Rsin(theta) makes the wedge have a horizontal acceleration, but which force (or component of a force) provides the small mass with that horizontal acceleration?

    • @milessodejana2754
      @milessodejana2754 ปีที่แล้ว

      That's why it's called a ghost force.

  • @naveens800
    @naveens800 9 ปีที่แล้ว

    nice video...helped me a lot..

  • @aryanparekh9314
    @aryanparekh9314 ปีที่แล้ว

    There are no forces to acting on the block to let it keep going with the wedge, why would it have any acceleration in the same direction as that of the wedge? all the normal forces act in the opposite direction

    • @boranxiii
      @boranxiii 8 หลายเดือนก่อน

      you should think of it as one body.Because the direction they are going to is the same,so are the velocity and acceleration vectors.

    • @jesusk1358
      @jesusk1358 19 วันที่ผ่านมา

      @@boranxiii They are going at the opposite directions. One is moving left and the other is moving right.

  • @laxmi_reels
    @laxmi_reels 3 ปีที่แล้ว

    Thanks alot sir 🙏💐

  • @ishaankulkarni1396
    @ishaankulkarni1396 5 ปีที่แล้ว

    This was great. Watched it for JEE advance revision

  • @jaysun1309
    @jaysun1309 4 ปีที่แล้ว

    Thank you!

  • @gamingzeraora443
    @gamingzeraora443 9 หลายเดือนก่อน

    just use psuedo force and convert it into a rested block

  • @barzipori8564
    @barzipori8564 5 ปีที่แล้ว

    An amazing job. thanks a lot!

  • @alejandrodeharo9509
    @alejandrodeharo9509 4 ปีที่แล้ว +1

    the solutionary of physics sears zemansky book provider has a different answer

  • @ModernTruthRevelation
    @ModernTruthRevelation 6 ปีที่แล้ว +1

    tam bir bakkal hesabı. şaka gibi. neyse gene de benzeri olmayan bir sorunun çözümü o yüzden teşekkürler.

  • @HarshRajAlwaysfree
    @HarshRajAlwaysfree 7 ปีที่แล้ว

    oh the video with sound was here

  • @rmsvideos1335
    @rmsvideos1335 7 ปีที่แล้ว

    Where the heck does mAcos theta come from around 10 min

  • @superdoer
    @superdoer 9 ปีที่แล้ว

    thanks!

  • @arnavsingh5197
    @arnavsingh5197 4 ปีที่แล้ว

    AMAZINGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG!!!!!!!!!!!!!!!!!1

  • @batuhansaroglu7434
    @batuhansaroglu7434 2 ปีที่แล้ว

    acil İngilizce öğrenmem lazım

  • @debjitgangopadhyay7713
    @debjitgangopadhyay7713 4 ปีที่แล้ว

    Lol

  • @lakshgoyal1324
    @lakshgoyal1324 2 ปีที่แล้ว

    He did not give clear understanding

  • @sameeraggarwal782
    @sameeraggarwal782 7 ปีที่แล้ว +2

    G is down....i don't care!! Damn😂

  • @lakshgoyal1324
    @lakshgoyal1324 2 ปีที่แล้ว

    😡😡😡😡😡

  • @lakshgoyal1324
    @lakshgoyal1324 2 ปีที่แล้ว

    He wasted my time

  • @lakshgoyal1324
    @lakshgoyal1324 2 ปีที่แล้ว

    poor explanation

  • @deltaagartala6530
    @deltaagartala6530 7 ปีที่แล้ว +1

    total waste of 26 minute from my course.