The hallow 6061-T6 aluminum shaft has an outer and inner radius of of c0 = 40mm and ci = 3...

The hallow 6061-T6 aluminum shaft has an outer and inner radius of of c0 = 40mm and ci = 30mm, respectively. Determine the angle of twist iof end A. the flexible support at B has a torsional stiffness of has a torsional stiffness of k = 90 kN •m/rad.