Problem $2(25$ pts$.)$

Given: Column ABC has a uniform rectangular cross section with $b=120mm$ and $d=220mm.$ The column is fixed at $B$ and pinned at A and is braced in the $xz$ plane at its midpoint $C.$ Let $P=900kN$ and $E=200$GPa.

Find:

a$)$ The critical stress in the $x-$direction and $y-$direction.

b$)$ If the column is adequare for the applied load.