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Linear density

  1. Nov 13, 2004 #1
    I had a problem with finding the moment of inertia. I have a rod and it has linear density[tex]\lambda=4.0kg[/tex] and the equation for its moment of inertia is [tex]I=\frac{1}{12} ML^2[/tex] now I have an axis at the center of mass of a rod the rod has a total length [tex]L=4m[/tex] so in my equation I would have to substute [tex]\lambda L=M[/tex] now the thing that I dont understand is if my center of mass horizontal cordinate is [tex]2m[/tex] the length I multipy by lambda should be 2m correct?
  2. jcsd
  3. Nov 14, 2004 #2
    Kg is not the unit for linear density. I'm assuming you meant [itex]4.0\frac{kg}{m}[/itex]. If each meter of the rod has a mass of 4.0kg, why would you only multiply by half the length of the rod to get its mass? I think [itex]M=(4.0\frac{kg}{m})(4.0m)[/itex]. Does that give you the right answer?
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