Answer Happy

Solve for both figures 10.12 and 10.13, please
10.12 A compression member of 1.5-m effective length consists of a solid 30-mm-diameter brass rod. To reduce the weight of the member by 25%, the solid rod is replaced by a hollow rod of the cross section shown. Determine (a) the percent reduction in the critical load, (b) the value of the critical load for the hollow rod. Use E = 200 GPa. 10.13 Determine (a) the critical load for the brass strut, (b) the dimension d for which the aluminum strut will have the same critical load, (c) the weight of the aluminum strut as a percent of the weight of the brass strut. A 1.1 m Brass 20 mm B E = 120 GPa p=8740 kg/m³ Fig. P10.13 1.1 m D Aluminum E = 70 GPa p=2710 kg/m³ 30 mm Fig. P10.12 m B 15 mm 30 mm 1 m 25 mm