4 When an HSS tool is used to turn a stainless-steel shaft, the cutting force can be predicted: F_{c}=151,000 f^{0.55} a_{p}^{0.96} The recommended speed is 200 fpm and the feed

is 0.03 ipr. The diameter of the work-piece is 3 in. and the final diameter is 2.8 in. The part is 4 in. long. A 10-hp motor is used todrive the machine, which has an efficiency of 0.90. What is the maximum depth of cut,based on the power-consumption constraint? How long will it take to finish the work-piece?