$5-6.$ The solid shaft has a diameter of $0\mathrm{.}75$ in$.$ If it is subjected

to the torques shown, determine the maximum shear stress

developed in regions $BC$ and $DE$ of the shaft. The bearings at

A and $F$ allow free rotation of the shaft.

$5-7.$ The solid shaft has a diameter of $0\mathrm{.}75$ in $.$ If it is

subjected to the torques shown, determine the maximum

shear stress developed in regions $CD$ and $EF$ of the shaft.

The bearings at A and $F$ allow free rotation of the shaft.

$5-29.$ The steel shafts are connected together using a fillet

weld as shown. Determine the average shear stress in the

weld along section $a-a$ if the torque applied to the shafts is

$T=60N*m.$ Note: The critical section where the weld fails

is along section $a-a.$