Consider column buckling on an aluminum 6061-t6 rectangular tube with 2" * 4" outer dimensions and 0.5" wall thickness. assume young's modulus E = 10(10)^6 psi, the Yield Strength Sy = 40,000 psi, The Lenght l = 60 in and compressive load P = 30,000. Determine the safety factor N for the following boundary conditions:
a) Pinned - Pinned
b) Fixed - Fixed