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Homework Help: D'alembert's Principal

  1. Feb 26, 2006 #1

    Q. use d'alemberts principal to find the condition of static equilibrium


    i prolly want to look at the coordinates of the system with respect to theta

    x = L sin Theta where L is the length of the string

    y = - L cos theta

    (Fapplied - Finertial) delta r = 0

    Im guessing the F applied is both the horizontal force and the force of gravity

    and that the inertial force is m * L * theta (double dot)

    delta r = L * delta theta

    so im just wildly guessing that

    (Fapplied - Finertial) delta r = 0
    (Fsin theta + mg cos theta - m * L * theta (double dot) ) delta r = 0

    i know im wrong but maybe someone can tell me what im doing wrong
  2. jcsd
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