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Triangular shaft change to circular shaft

  1. Jan 3, 2017 #1
    1. The problem statement, all variables and given/known data
    for the circular cross section shaft , why we need to put an sin60 as to get the area ?

    2. Relevant equations

    3. The attempt at a solution
    why the area shouldnt be pi(0.004) ^2 only ?

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  3. Jan 3, 2017 #2


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    The author doesn't. This sine appears in the calculation of the area of the triangular shaft
    Nothing ?
    That's not an attempt at solution. Where do you see this value ? I don't even see it appearing anywhere. All I see is ##\pi c^2## which is a reasonable expression for the area of a circle with radius ##c##.
  4. Jan 3, 2017 #3


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    Staff: Mentor

    The author is calculating the area of the equilateral triangle, using ½×base×height

    He then equates this area to that of a circle of radius c and is able to calculate the value of c.

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