b$)$ A vehicle, which is idealized as the three point loads spaced as shown below, moves across the truss on beams at the level of the upper chord of the truss. Calculate and show the influence line for force in member $\backslash (\backslash$mathrm$\{$U$\}\_\{2\}-\backslash$mathrm$\{$L$\}\_\{1\}\backslash ).$ Show the maximum and minimum ordinates on a sketch of the influence line and calculate the maximum compression force in member $\backslash (\backslash$mathrm$\{$U$\}\_\{2\}-\backslash$mathrm$\{$L$\}\_\{1\}\backslash )$ caused by the vehicle as it crosses the structure.