For example, let’s examine the pitching moment imposed on a wing cross-section, caused by an aileron deflection movement downward. Assume the centroid is at the midpoint of the wing chord (not including the aileron). Using the examples provided in the presentation slides, what will be the pitching moments for the following upward forces: 20 lbs., 30 lbs., 40 lbs., and 50 lbs.? Can you now see why a wing needs a certain amount of rigidity? Please explain.