A tensile$-$testing apparatus is to be constructed that must withstand a maximum load of $220,000N(50,000lbf).$ The design calls for two cylindrical support posts, each of which is to support half of the maximum load. Furthermore, plain$-$carbon $(1045)$ steel ground and polished shafting rounds are to be used; the minimum yield and tensile strengths of this alloy are $310$MPa$(45,000)$ and psi $),$ respectively. Specify a suitable diameter for these support posts.