5(20 points) It is known the rotary speed of the shaft is n=500r/min, and the input power of driving wheel A is PA=600kW, and the output power of driven wheel BC and D are PB=200kW,PC=300KW,PD=100Kw, respectively. The Allowable shearing stress is [T]=120MPa. Determine: (1) The torque applied to each segment of the circular shaft. (2) If each segment has the same diameter, try to determine the diameter D