A hollow circular shaft has a wall thickness t = 10mm and an inner diameter d_inner = 69 mm. If the shaft is to be subjected to a torque T = 8 N.m, then the maximum shear stress expected in the shaft:
Note: J = (c - c) where: Co: shaft's outer radius, Ci: shaft's inner radius
a. 70.15 KPa
b. 24.71 KPa
c. 90.48 KPa
d. 143.44 KPa