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tn3003
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Homework Statement
This is the cross sectional are of the shape: http://img38.imageshack.us/i/shapep.jpg/"
It's made of 2 10"x1" plates. (Picture is not to scale)
Q (first moment of inertia) above and below the neutral axis should be the same. For some reasons, my calculated Q above is not equal to Q below the NA.
The Attempt at a Solution
Taking the datum at the bottom
y bar = (10*0.5 + 10*6) / (20) = 3.25"
Q above = 7.75 * 2.75 = 21.31
Q below = 2.25 * (2.25/2) + 10 * 2.75 = 30.03
21.31 =/= 30.03
Someone please point out my mistake.
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