To provide access to the interior of a hollow square tube of 0.25-in. wall thickness, the portion CD of one side of the tube has been removed. Knowing that the loading of the tube is equivalent to two equal and opposite 15-kip forces acting at the geometric centers A and E of the ends of the tube, determine (a) the maximum stress in section a-a, (b) the stress at point F. Given: The centroid of the cross section shown is at C and I; = 4.81 in“.

Fig: 1

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