Q$\mathrm{.}3.$ At room temperature $(20C)$ A $0\mathrm{.}5-mm$ gap exist between the ends of the rods shown. At a later time the temperature has reached $140C.$ Determine

a$)$ the normal stress in the aluminum rod b$)$the change in the length of aliminum rod

Aluminum

$A=2000m{m}^2$

$E=75$GPa

$=23\frac{{10}^{-6}}{}C$

Stainless steel

$A=800m{m}^2$

$E=190$GPa

$=17\mathrm{.}3\frac{{10}^{-6}}{}C$