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      <title>Centroid/1st Moment</title>
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      <div class="title_topic3" id="xps10_pagetitle">Centroid/1st Moment</div>
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      <p class="para_topic">The center of mass, or centroid, is the point XC,YC given by</p>
      <p align="center"><img align="bottom" src="graphics/ana_infoat54.gif"></p>
      <p class="para_topic">where:</p>
      <p class="para_topic">A is the area, My is the first moment relative to the YC axis, and Mx is the first moment relative to the XC axis.</p>
      <p class="para_topic">The center of mass can be thought of as the point that would be the balance point if the plane area were a thin, uniform plate.</p>
      <p class="para_topic">The system calculates the first moments of the specified region about the XC and YC axes using the formula:</p>
      <p align="center"><img align="bottom" src="graphics/ana_infoat53.gif"></p>
      <p class="para_topic">where:</p>
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               <p class="para_td">I</p>
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               <p class="para_td">is the required first moment</p>
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               <p class="para_td">r</p>
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               <p class="para_td">is the signed distance from the specified axis</p>
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               <p class="para_td">A</p>
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               <p class="para_td">is area</p>
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      </table><br><p class="para_topic">The quantity I has dimension L3 (length3) and may be expressed in inches3 or millimeters3. The moment is the twisting force, or torque, around the XC or YC axis that results from the weight of the object. As the weight of the object increases or its distance from the axis increases, the moment around that axis increases proportionately.</p>
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