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Homework Help: What is the tension in the strings when the slender bar begins oscillating

  1. Feb 24, 2017 #1
    1. The problem statement, all variables and given/known data
    There is a uniform slender bar which is suspended by two light inextensible strings and hangs in equilibrium. (if the mass and length of the bar are m and 2b )

    Now, someone slightly knocks one end to make the bar rotate around the vertical axis with initial angular velocity ω0.

    I want to know two things

    (1) what is the tension in the strings when the slender bar begins to rotate?

    (2) What is the rotation angle of the bar when the center of mass reaches its highest position?
    2. Relevant equations

    ΣF=0,ΣMG=0 equilibrium equations

    ΔT=−ΔV Low of conservation of mechanical energy

    3. The attempt at a solution

    Can I use the equilibrium equations and conservation of mechanical energy for these problems?
    Last edited: Feb 24, 2017
  2. jcsd
  3. Feb 24, 2017 #2


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  4. Feb 25, 2017 #3


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    Once the bar is set into rotation, the equilibrium equations are no longer valid. Question (1) will require application of dynamics.
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