3. For a bolted assembly with six bolts, the stiffness of each bolt is kb=3 Mlbf/in and the stiffness of the members is km=12 Mlbf/in per bolt. An external load of 80 kips is applied to the entire joint. Assume the load is equally distributed to all the bolts. It has been determined to use ½ in-13 UNC grade 8 bolts with rolled threads. Assume the bolts are preloaded to 75 percent of the proof load. a) Determine the yielding factor of safety b) Determine the load factor of safety c) Determine the factor of safely based on joint separation