For the beam shown below:

If the beam has a nominal size of $2"$x $6",$ and the maximum shear force is $70$ lb $,$ compute the shear stress.

$12\mathrm{.}7$ psi

None of these answers

$8\mathrm{.}5$ psi

$10\mathrm{.}4$ psi

$8\mathrm{.}8$ psi