The Solid $50mm$ diameter shaft used to transmit the torques applied to the gears. Determine the angle of twist of end A with respect to end D$.$ Take $G=80$GPa

$(50$ points$)$

Note: First You need to pass a section through each member, then calculate the internal torque at each member. Then calculate the angle of twist of end A with respect to end $D$ using the formula:

$={\displaystyle \underset{?}{\overset{?}{}}}\frac{TL}{JG}$