$10-38.$ The $60-mm-$diameter shaft is made of $6061\mathrm{.}16$

aluminum having an allowable shear stress of ${}_{\text{a}\text{l}\text{l}\text{o}\text{w}}=80MP$

Determine the maximum allowable torque T$.$ Also, find the

corresponding angle of twist of disk A relative to disk C$.$V

$10-39.$ The $60-$mm$-$diameter shaft is made of $6061*-76$

aluminum. If the allowable shear stress is ${}_{\text{a}\text{l}\text{l}\text{o}\text{w}}=80M{P}_2,$

and the angle of twist of disk A relative to disk $C$ is limited

so that it does not exceed $0\mathrm{.}06$ rad $,$ determine the maximum

allowable torque $T.$