1. Calculate the angle of twist θ a 4-in.-diameter solid steel shaft 20 ft long. The shaft is subjected to a torque of 40,000 lb-in.
2. A 1-in.-diameter solid steel shaft, 60 in. long, was tested in a large torsion machine. An angle of twist of 5° was measured when the shaft was subjected to a torque of 1700 lb-in. Calculate the modulus of rigidity G.