A small leaf spring b=10mm wide by L=125 mm long by t mm thick is simply supported at it...

A small leaf spring b=10mm wide by L=125 mm long by t mm thick is simply supported at its ends and subjected to a center load P that varies continuously from 0 to 20 N (Fig. P4.39). Using the modified Goodman criterion, determine the value of t, given a fatigue strength MPa, and safety factor of n=2.5