$C_{**}$ Prob. $2\mathrm{.}8-17.$ The pin$-$jointed planar truss shown in Fig. P$2\mathrm{.}8-17$ is to be made of three steel two$-$force members and is to support vertical loads $P_B=2$kips at joint $B$ and $P_C=3$ kips at joint $C.$ The lengths of members $AB$ and $BC$ are $L_1=30$ in $.$ and $L_2=24in.,$ respectively. Joint $C$ is free to move vertically. For the steel truss members, the allowable stress in tension is $({}_T{)}_{\text{a}\text{l}\text{l}\text{o}\text{w}}=20$ksi, the allowable stress in compression

P$2\mathrm{.}8-17$