申論題

Prob.#4(30%)
 The member shown in Figure 2(a) having a rectangular cross section is designed to resist a moment of 50 N. m. In order to increase its strength and rigidity, the engincer is planning to add two small ribs at its bottom, Figure 2(b). Is this a good idea? Answer this question by determining and comparing the maximum normal stress in the member for both cases.