We have a bar constrained between two walls with cross$-$

sectional area $1\mathrm{.}0c{m}^2,$ two sections of lengths $0\mathrm{.}5$ m and

$0\mathrm{.}3$ m $,$ elastic moduli $200$ GPa and $72$ GPa $,$ and linear

coefficients of thermal expansion $121e-\frac{6}{K}$ and $231e-$

$\frac{6}{K}.$ If there is a change in temperature of $189$ K $,$ what is

the displacement of the centerline between the two

sections to the right in units of microns?