4.A compression spring has a diameter of 0.67 in and a coil diameter of 0.067 in, with 30 total coils. The spring is to be made of unpeened HD A227 wire and have squared and ground ends. Find the fatigue factor of safety when repeatedly cycled from 0 to 10.3 lbf. Use the Gerber fatigue criterion and the Zimmerli data.
