Engineering Board Exam Reviewer · Applications: Centroid, Work, and Moment of Inertia · medium

Find the distance of the centroid of a quarter-circular area of radius 6 from either straight edge.

  1. 4/π 1.273
  2. 6/π 1.91
  3. 12/π 3.82
  4. 8/π 2.546

Answer

D. 8/π 2.546

Solution

A=π(6)2/4=9π. x= 1A 06xsqrt(36-x2),dx=1/9π≤ft[- 13(36-x2)3/2 ]06=72/9π= 8π (the formula 4r/3π).

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