Give the following problem a try. If you get stuck, here is one way to work it: Essential Solution Video.

A load $P$ will be supported by a structure consisting of a rigid bar ABCD, a polymer $E=2,300$ksi;$=2\mathrm{.}9\frac{{10}^{-6}}{}F$ bar $(1)$ and an

aluminum alloy $E=10,000$ksi;$=12\mathrm{.}5\frac{{10}^{-6}}{}F$ bar $(2),$ as shown. Each bar has a cross$-$sectional area of $2\mathrm{.}00$ in$.{?}^2.$ The bars are

unstressed when the structure is assembled at $30F.$ After a concentrated load of $P=32$ kips is applied and the temperature is

increased to $100F,$ determine the normal force in bar $(1).$

$3\mathrm{.}85$ kips

$4\mathrm{.}15$ kips

$2\mathrm{.}59$ kips

$3\mathrm{.}60$ kips

$2\mathrm{.}30$ kips