A 3-m-long fixed-ended column (Le = 1.5 m)is made of a solid bronze rod of diameter To r...

A 3-m-long fixed-ended column (L_e = 1.5 m)is made of a solid bronze rod of diameter To reduce the weight of the column by 25%, the solid rod is replaced by the hollow rod of cross section shown in Fig. P11.12. Compute (a) the percentage of reduction in the critical load and (b) the critical load for the hollow rod.