$(5)$ A hollow steel $E=30,000$ksi tube $(1)$ with an outside diameter of $3\mathrm{.}50$ in$.$ and a wall thickness of $0\mathrm{.}216$ in$.$ is fastened to a solid $2-$in$.-$diameter aluminum $[$E $=10,000$ksi $]$ rod. The assembly is attached to unyielding supports at the left and right ends and is loaded as shown in the Figure below. Determine:

a$.$ the stresses in all parts of the axial structure.

b$.$ the deflections of joints $B$ and $C.$