A cast iron workpiece is turned on a lathe whose mechanical efficiency = 0.87. Cutting speed = 400 ft/min, feed = 0.011 in/rev, and depth of cut = 0.120 in. Cutting force = 250 lb. Determine (a) the horsepower consumed by the turning operation; (b) horsepower that must be generated by the lathe; (c) unit horsepower and specific energy for the work material in this operation.