-For a bolted assembly, two plates of cast iron are clamped together. Each cast iron assembly part has 0.75 inch thickness. The bolt is ¾½ in – 16UNF × 2½ in SAE grade 5. (UNF-Fine Series). A fluctuating - external load is applied to the entire joint with Pmax=120 kips and Pmin=60 kips. a) Calculate the minimum number of bolts necessary to avoid joint seperation. b) In the same bolted assembly, assume 15 bolts are used and calculate the fatigue factor of safety using the Goodman theory. -Explain self-locking condition and determine the roles of lead angle and friction coefficient in self locking. Given Data: -Bolt material is steel and both assembly parts are cast iron (Esteel: 30 Mpsi, Ecast iron: 14 Mpsi) -Applied preload is 75 percent of the proof load (Fi=0.75Fp) and Fp=At.Sp, -Endurance strength of bolt is 18.6 kpsi -Sut (ultimate tensile strength), A₁ (tensile stress area) and Sp (proof strength) of bolt should be found from the corresponding tables in your textbook.