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Homework Help: Torque/Lever HELP!

  1. Oct 27, 2008 #1
    1. The problem statement, all variables and given/known data
    What is the mass of the meter stick, which is shown in the sketch below while it is balanced?

    http://img252.imageshack.us/img252/9819/problemeo4.jpg [Broken]
    a 160 grams b 120 grams c 80 grams d 200 grams e none of the above
    2. Relevant equations



    3. The attempt at a solution

    I am completely CONFUSED! Our professor never discussed finding the mass of the lever.
     
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Oct 27, 2008 #2
    The meter, you can think of like a mass that adds torque to the system. Consider the each side of the meterstick as a mass concentrated at that center of gravity for the side. Then you can solve for the sum of the torques = 0.
     
  4. Oct 27, 2008 #3
    To reiterate what thepanda said, think of the leaver as mass less, and simply assume there is a mass of "x" weight hanging from the 50cm mark of the meter stick (20cm to the right of the fulcrum). Simply solve for "x".

    *It is placed here because it is the object's center of mass
     
  5. Oct 27, 2008 #4
    Okay I know I am going to sound completely stupid, but I am still getting really confused. I have a political science degree and working on a history degree. I am in the lowest level physics and I am still getting really confused.

    Sorry.
     
  6. Oct 27, 2008 #5
    so does X = 120 grams?
     
  7. Oct 27, 2008 #6
    that is the correct answer.
     
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