An aluminum tube is required to transmit an axial tensile force $P=148 \mathrm{kN}$ (see figure part a). The thickness of the wall of the tube is to be $6 \mathrm{mm}$.
(a) What is the minimum required outer diameter $d_{\min }$ if the allowable tensile stress is $84 \mathrm{MPa} ?$
(b) Repeat part (a) if the tube will have a hole of diameter $d / 10$ at mid-length (see figure parts b and c).
