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How can you explain how a balance works vectorially?

  1. Aug 6, 2005 #1
    you have a balance with 1kg weight in each 1 meter long arm

    when its horizontal each 10 N force * 1 m long will balance so the balance wont move

    but when you lean the balance 45º the vertical force will be cos 45 * 10 N in each arm so the balance should stay in that position since the forces are equal but it tend to level horizontal

    can anyone explain this please
  2. jcsd
  3. Aug 6, 2005 #2


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    All I can do is ask where you got the idea that a balance in such a situation would tend to leve!
  4. Aug 7, 2005 #3
    its not only what basics physics say but besides i have tested it myself in case that basic physics were wrong
  5. Aug 7, 2005 #4
    I am betting it has to do with the force between the ballance and the central support. I am guessing, that in your (non-ideal) experiment the force from the support is no longer symmetrical once the balance is tilted.
  6. Aug 8, 2005 #5
    im afraid i disagree basic physics says a balance will balance or level with equal weights in its arms

    the problem is that you cant prove it vectorially what doesnt mean the balance wont level simply vectors fail to explain a simple physical process
  7. Aug 8, 2005 #6
    besides if you put 1kg in one arm and 2 kg in the other arm and aply vectors the balance will tend to put vertical according to vectors but balances dont behave that way

    i insist vectors fail to explain how a balance works
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