The simply$-$supported beam shown below $($length $L=51\mathrm{.}4$ in$)$ has a circular

cross$-$section with the following properties:

$d=2in$

$A=3\mathrm{.}14i{n}^2,I_z={\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}{y}^{2}dA=0\mathrm{.}785i{n}^4,I_y={\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}{z}^{2}dA=0\mathrm{.}785i{n}^4,$ and

$J={\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}(y^2+z^2)dA=1\mathrm{.}57i{n}^4$

If the beam is subjected to a pure moment load of $M=422$hat$(j)+1081$hat$(k)$ in$-$lb at

the center, what is the maximum shear stress $({}_{\text{m}\text{a}\text{x}})$ in the material $($in units of

ksi, expressed as a positive number?