A rod is fixed to a wall with a force of $-20l{b}_f$ applied to the right end of the rod. Specific dimensions and Young's moduli are provided here:

$r_1=4in$

$r_2=2in$

$L_1=6in$

$L_2=3in$

$E_{\text{a}\text{l}\text{u}\text{m}\text{i}\text{n}\text{u}\text{m}}=10\frac{{10}^6}{P}SI$

$E_{\text{b}\text{r}\text{a}\text{s}\text{s}}=14\mathrm{.}5\frac{{10}^6}{P}SI$

Brass

Aluminum

Create local and global stiffness matrices for the problem above. Determine the nodal displacements and the reaction force.