Question $11\mathrm{.}9-14$ A plane truss is subjected to loads $2$P and P at joints B and C$,$ respectively, as shown in the figure part a$.$ The truss bars are made of two steel angles $($cross$-$sectional area of the two angles,A $=2180$ mm$?,$ and thickness $=6\mathrm{.}4$ mm$,$ see figurepart b$)$ having an ultimate stress in tension equal to$390$ MPa. The angles are connected to a $12-$mm$-$thick gusset plate at C $($figure part c$)$ with $16-$mm diameter rivets; assume each rivet transfers an equal share of the member force to the gusset plate. The ultimate stresses in shear and bearing for the rivet steel are$190$ MPa and $550$ MPa, respectively.Determine the allowable load Pallow if a safety factor of $2\mathrm{.}5$ is desired with respect to the ultimate load that can be carried. Consider tension in the bars,