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Homework Help: Swinging Pendulum

  1. Apr 29, 2009 #1
    1. The problem statement, all variables and given/known data

    A pendulum is mounted on a vertical, rotating
    shaft by means of a hinge. The shaft is free
    to rotate in its bearings. Use conservation laws to
    eliminate one degree of freedom and simulate the
    motion of the other one. Analyse and comment
    using mechanical terms.


    3. The attempt at a solution

    I started out with the Energy principle: E = constant = Kinetic + Potential
    U = Potential------I = Moment of inertia
    K= Kinectic------w = angular velocity
    m = mass------v = velocity
    L = Length------ θ = Angle

    K = ½(*I*w2+*m*v2)

    U = -½*m*g*L*cos θ

    And i have no idea what to do next, i think i perhaps should derive the energy expression, but i dont know what to derive on, time,angle?

    Thank you!
  2. jcsd
  3. May 7, 2009 #2
    Sorry, problem with image

    Here it is

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