Example

The pin$-$comnected structure shown in the

figure consists of a rigid bar ABCD and two

axial members. $\frac{?}{\text{B}\text{a}\text{r}}(1)$ is steel $[E=200$GPa,$$

$=11\mathrm{.}7\frac{{10}^{-6}}{P}C]$ with a cross$-$sectional area of

$($a$)$ the normal stresses in bars $(1)$ and $(2).$

$($b$)$ the deflection of point $D$ on the rigid bar.