A3-in. diameter low-strength, stainless-steel cylindrical part is to be turned on a lathe at 600 rpm, with a depth-of-cut of 0.2-in. and a feed of 0.025 in./rev. what should be the minimum horsepower of the lathe?

Ahelical coil spring has a mean diameter of 50 mm, a wire diameter of 5.5 mm and is wound with a pitch of 10 mm. the spring steel has an ultimate strength of 1250 mpa. find the force needed to compress the spring solid and the wire stress in this condition. state whether the spring will return to its initial length.