a) An internal combustion engine of 100 horsepower (hp) transmits power to the car wheels of an automobile at 600 rev/min (rpm). Neglecting any transmission losses, determine the minimum permissible diameter of the solid circular section steel shaft if the maximum shear stress in the shaft is limited to 75MPa. What will be the resulting angle of twist of the shaft, due to the applied torque, over a length of 1 m? Assume that the rigidity modulus, G = 50 GPa. (Note that 1 hp = 745.7 W). b) If the shaft in task 3a was replaced by a hollow tube of the same external diameter, with a wall thickness of 0.01 m, and is subject to the same applied torque, determine the maximum shear stress in the shaft, and the resulting twist of the shaft. The material properties of the shaft may be assumed to be the same as those in 3a.