Problem $2$ : For the truss shown below,

$($a$)$ Use the principle of virtual work to determine the horizontal deflection at joint $E$ of the truss shown

below due to a temperature increase of $50C$ in members $AC$ and $CE$ only.

$($b$)$ Use the principle of virtual work to determine the horizontal deflection at joint $E$ of the truss shown

below if member $BC$ is $18mm$ too long and member $CE$ is $15mm$ too short..

$=1\mathrm{.}2\frac{{10}^{-5}}{}C$