physics
posted by stacey graham on .
A stairwell is supported by two circular steel rods at one end. The other end supported above. The two steel rods are subjected to a total load of 12,800lbs. The rods are 24 ft long and E=30*10^6 psi. Select the rod based on the following specs. The rod deformation should not exceed 0.375 inches and the allowable tensile stress is 10,844 psi?

This seems to be more a "strength of materials" or civil/mechanical engineering design question than a physics problem.
Assume each rod gets half the load, or 6400 lb. Calculate the minimum circular area required to satisfy both the stress and the deflection requirements. From an available stock catalog for mild steel, pick the smallest diameter that satisfies both requirements. 
I calculated reqd A got 32.8 psi to get diameter of 6.46 in/in. Am I going right way or did I miss something?

You missed something. 32.8 psi is hardly any stress at all.