Rigid bar ABCD is supported by a pin connection at A and by two axial bars $(1)$ and $(2).$ Bar $(1)$ is a $39-$in$.-$long bronze $[E=17200$ksi bar

with a cross$-$sectional area of $0\mathrm{.}86i{n}^2.$ Bar $(2)$ is a $36-$in$.-$long aluminum alloy $[\{$:$E=10000$ksi$]$ bar with a cross$-$sectional area of $1\mathrm{.}51in.{?}^2.$

Assume $L_1=39in.,L_2=36in.,a=35in.,b=53in.,$ and $c=21in.$ Both bars are unstressed before the load $P$ is applied. If a concentrated load

of $P=24$ kips is applied to the rigid bar at $D,$ determine:

$($a$)$ the normal stresses ${}_1,{}_2$ in bars $(1)$ and $(2).$

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

Answers:

$($a$){}_1=$

ksi,${}_2=$

ksi

$($b$)v_D=$

in$.$