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Balance beam help?

  1. Dec 13, 2011 #1
    1. The problem statement, all variables and given/known data

    5. (12)A balance beam device comprised of a 200 cm long beam of unobtainium (no mass) ]
    \]and a fulcrum located in the middle of the beam is balanced straight and level. At the right side of the beam system a mass of 30 kg is attached and at the other end of the beam system a mass of 25 kg is attached.

    a) the torques acting on the system

    b) the net torque and direction of rotation

    c) Yippie the wonder dog, well beyond the prime of life, sees the problem of the unbalanced system with failing eyes. Yippie leaps up to the top of the fulcrum and after a less than stellar landing at the fulcrum point begins limping about on the left side of the fulcrum. The years have not been kind; our beloved Yippie has porked out to 25 kg (table orts you know). Help out, where must Yippie sit to bring the system into balance?

    2. Relevant equations

    3. The attempt at a solution

    I missed this lecture and am absolutely not understanding this. Can someone please solve this + explain at each step?
  2. jcsd
  3. Dec 14, 2011 #2
    You'd do best to read up on torques, you'll be spending a while on this stuff and having a good understanding from the get go will put you miles ahead.


    Try this video lecture (and any from this series if you're having troubles), they really are golden.
    http://video.google.com/videoplay?docid=6480119270481031622 [Broken]
    Last edited by a moderator: May 5, 2017
  4. Dec 14, 2011 #3
    i understand torque, i just dont understand how to balance these out and what not..i really need to see it solved to really get it x_x
    Last edited by a moderator: May 5, 2017
  5. Dec 14, 2011 #4
    In that case why don't you give (a) a stab, you just need to calculate the torque from each weight (distance x force).
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