A $1\mathrm{.}25-$in$.-$diameter solid circular shaft is made of a material that is assumed to be elastoplastic with $IY=18$ksi and $G=11\mathrm{.}2{10}^6$ psi.

For an $8-$ft length of the shaft, determine the maximum shearing stress and the angle of twist caused by a $7\mathrm{.}6-$kip$-$in$.$ torque.

The maximum shearing stress is

ksi.

The angle of twist caused by a $7\mathrm{.}6-$kip$-$in$.$ torque is