A brass pipe having the cross section shown has an axial load $\mathbf{P}$ applied $5 \mathrm{mm}$ from its geometric axis. Using $E=120 \mathrm{GPa}$, determine $(a)$ the load $\mathbf{P}$ for which the horizontal deflection at the midpoint $C$ is $5 \mathrm{mm},(b)$ the corresponding maximum stress in the column.