To find the bending moment of a 9' long square tubing (3x3x1/4" A36) fixed at one end and free at the other, the moment of inertia for the cross-section and the distance from the stress plane to the central axis are required. The load being suspended from the free end contributes to the bending moment, and understanding the connection at the fixed end can enhance accuracy, though assuming rigidity is acceptable. Resources for calculating deflection and bending moments are available online, providing formulas and examples. Clarification was made regarding the dimensions of the tubing, confirming it is indeed 3x3x1/4". Accurate calculations are essential for proper structural analysis.