A circular bar of 500 mm length is supported freely at its two ends, It is acted upon by a central concentrated cyclic load having a minimum value of 2000 kgf and a maximum value of 5000 kgf. Determine the diameter of bar by taking a factor of safety of 1.5, size effect of 0.85, surface finish factor of 0.9. The material properties of bar are given by: ultimate strength of 65 kgf/mm2, yield strength of 50 kgf/mm2, and endurance strength of 35 kgf/mm2.