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Static Equilibrium and tension

  1. Apr 13, 2007 #1
    1. The problem statement, all variables and given/known data
    A 10-m uniform beam of weight 100 N is supported by two ropes at its ends. If a 400 N person sits at 2.0 m from the left end of the beam, what is the tension in the left rope?

    I thought the answer would be:
    3. The attempt at a solution
    100*5 + 400*7 = T*10
    3300 = T*10

    T = 330 N

    But it's not correct. What am I doing wrong?

    A book weighs 6 N. When held at rest above your head the net force on the book is? I say -6 N. Is this correct?

  2. jcsd
  3. Apr 13, 2007 #2
    Ah simple math error. It's 370.
    Any feedback for the other question? I have another topic about the same subject that is actually more urgent. Thanks!
  4. Apr 13, 2007 #3
    -6 sounds like a good answer?
  5. Apr 13, 2007 #4
    The force exerted by your head on the book is 6 N. I would not call this the net force though. The net force on the book is 0 because it is *at rest*.
  6. Jan 17, 2009 #5
    ya i think you are right
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