A-2.8: A steel rod (E = 210 GPa, d, = 12 mm, cte = 12 x 10-6/C) is held stress-free between rigid walls by a clevis and pin (d, = 15 mm) assembly at each end. If the allowable shear stress in the pin is 45 MPa and the allowable normal stress in the rod is 70 MPa, the maximum permissible temperature drop AT is approximately: (A) 14 C (B) 20 C (C) 28 C (D) 40 C Pin, dp AT Rod, dr Clevis