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Homework Help: Finding moment of inertia

  1. Jan 2, 2010 #1
    a uniform solid block has mass 0.172 kg and edge lengths a=3.5cm, b=8.4cm, and c=1.4cm (c is the height of the rectangular solid).Calculate its rotational inertia about an axis through one corner and perpendicular to the large faces.

    i know the formula is integral of r^2 dm, but i have no idea what to do here. i have r^2 = a^2 + b^2. but i don't know how what to substitute for dm.
  2. jcsd
  3. Jan 2, 2010 #2


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    Hi demonelite123! :smile:

    (try using the X2 tag just above the Reply box :wink:)
    If r2 = x2 + y2, then dm = density times dxdydz (or, if you're only integrating over x and y, then dm = hdxdy). :smile:
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