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Spring-Mass System Matrix

  1. Mar 22, 2012 #1
    The differential equation that model an undamped system of 3 masses and 4 springs with external forces acting on each of the three masses is


    a)express the system using matrix notation x'=Kx+g(t) for the state vector x=(x1,x2,x3)T. Identify the matrix K and the input g(t).

    b) Give conditions m1, m2, m3, k1, k2, k3, k4 under which K is a symmetric matrix.

    I am pretty sure I have gotten the first part but I am having trouble even figuring out what the second part means. When I created my matrix K it seems like it is already a symmetric matrix. Any help would be great.
  2. jcsd
  3. Mar 22, 2012 #2


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    I don't undestand part (b) either.

    The equations you are given will be symmetric for any values of the m's and k's - so what was the question really asking you about :confused:
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