The solid shaft shown below is in equilibrium, supported at two bearings A and B. The pulleys C and D have diameters in the ratio 3:2. T₁ = 1000 N, T₂ = 500 N and T3 = 1500 N. The diameter of the shaft is 50 mm and yield strength sy = 400 MPa. The bearings do not exert any moments or axial forces on the shaft. a. If a factor of safety (n) of 3 is desired based on Maximum Shear Stress (MSS or Tresca) criteria, find the diameter of pulleys C and D. b. If n = 3 is desired based on the Distortion Energy Theory (DET or von Mises criteria), find the diameter of pulleys C and D.

Fig: 1