Prob. $3\mathrm{.}10-16.$ Each of the three truss members in

Fig. P$3\mathrm{.}10-16$ has a length $L$ and modulus of elasticity $E.$

The cross$-$sectional areas of the members are $A_1=A_2=A$

and $A_3=2A.($a$)$ Determine expressions for the horizon$-$

tal and vertical displacements, $u_A$ and $v_A,$ at joint A when

a horizontal load $P$ is applied to the right to the pin at

joint $A.($b$)$ Determine expressions for the axial forces$-$

$F_1,F_2,$ and $F_3-$in the three truss members when load $P$

is applied.

P$3\mathrm{.}10-16,$ P$3\mathrm{.}10-17,$ P$3\mathrm{.}10-18,$ and P$11\mathrm{.}5-40$