A conveyor belt is driven by a 7-hp motor turning at 1,100 rpm. Through a series of gears that reduce the speed, the motor drives the belt drum shaft at a speed of 12 rpm. If the allowable shear stress is 9.3 ksi and both shafts are solid, calculate(a) the required diameter of the motor shaft.(b) the required diameter of the belt drum shaft.

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.