Problem 1: A hollow shaft has to transmit 6MW at 150 rev/min. The maximum allowable stress is not to exceed 60MN/m² nor the angle of twist 0.3deg per meter length of shafting. If the outside diameter of the shaft is 300mm find the minimum thickness of the hollow shaft to satisfy the above conditions. G = 80 GN/m².

Problem 2: A steel shaft 3m long is transmitting 1MW at 240 rev/min. The working conditions to be satisfied by the shaft are:

That the shaft must not twist more than 0.02 radian on a length of 10 diameters,

That the working stress must not exceed 60 MN/m².

If the modulus of rigidity of steel is 80 Gn/m² what is

(a) The diameter of the shaft required

(b) The actual working stress,

(c) The angle of twist of the 3m length

Problem 3: For a solid or hollow shaft of uniform circular cross-section throughout its length, the theory of pure states that:

T/J = Gθ/l = r/R

Derive the above expression from first principals