For Problems $5\mathrm{.}5$ to $5\mathrm{.}15,$ determine the design moment strengths $M_n$ of the sections shown. Use $f_y=60,000$ psi and $f_c^{\text{'}}=4000,$ except for Problem $5\mathrm{.}9,$ where $f_c^f=5000$ psi. Check each section to see if it is ductile.

Problem $5\mathrm{.}11($Ans$.415\mathrm{.}8ft-k)$