A shaft ABCD is supported at one end A and at point C. The other end D consists of a pulley which has belt tensions in the vertical direction. The distance AD is 1200 mm. AC distance is 800 mm. A spur gear having pressure angle 20° is mounted at point B which is at a distance 400 mm from A. The diameter of pulley is 450 mm and that of the gear is 300 mm. The gear is supplied power equal to 20 kW at 500 rpm by another gear at the top of it. The tension on the tight side is 3 times the tension on slack side in the belt. The combined shock and fatigue factors for bending moment and torsional moment maybe taken as 1.5. The tensile strength of the material of the shaft and key is 700 MPa. Design the shaft and key for the pulley assuming factor of safety equal to 5. Assume allowance for the key way for stress as 0.75.