Problem 1. 3. A leaf spring in an automobile is subjected to cyclic stresses. The average stress 150 MPa; variable stress 500 MPa; ultimate stress = 630 MPa; yield point stress = 350 MPa and endurance limit=150 MPa. Estimate, under what factor of safety the spring is working, by Goodman and Soderberg formulae. [Ans. 1.75, 1.31