10. Important Notes When the moment results in compression at the upper layer of the structure, then the moment is +ve.
11. The bending strain is axial. The structure (beam) must be thin to satisfy Euler-Bernoulli theory. The second moment of area is similar to the moment of inertia but with the area instead of mass.
12. Sources Structure lectures by: Dr/ Mohamed Tawfik. Wikipedia.com Some web sites.