$3\mathrm{.}16($USCS Units$)$ A torque of $6000ft-lb$ is applied in a torsion test on a thin$-$walled tubular

specimen whose radius $=1\mathrm{.}5in,$ wall thickness $=0\mathrm{.}125in,$ and gage length $=2\mathrm{.}0in.$ This

causes an angular deflection $=1.$ Determine $($a$)$ shear stress, $($b$)$ shear strain, and $($c$)$ shear

modulus, assuming the specimen had not yet yielded. $($d$)$ If the specimen fails at a torque $=$

$8000ft-lb$ and an angular deflection $=20,$ calculate the shear strength of the metal.