As shown, I-beam ABC supports a sign that weighs S = 28 lb . The I-beam is 30 in. long and is further supported by a rod that is attached 18 in. from the wall. Assume that all forces acting on the I-beam act along its centroid and that the I-beam’s weight is negligible. Let the dimensions of the I-beam be w = 2 in. ,g = 1 in. , h = 2.6 in. , j = 0.7 in. , c = 5 in.

Part 1) Determine the moment of inertia I of I-beam ABC. Recall that in an I-beam, the flanges are the horizontal top and bottom sections and the web is the vertical section between the two flanges.

Part 2) Determine the absolute value of the bending moment in the beam at section a-a which is 5 in. from the wall.

Part 3) Determine the absolute maximum bending stress in the cross section at cut a-a using the flexure formula.
 

A -a -b L D B C S H j- h A -a -b L D B C S H j- h