Q$2$ The structural frame shown in Figure Q$2$ has a rigid and is rigidly jointed at both ends of the three columns. The mass of the structure of $5000kg$ is concentrated at the top. The columns are $3\mathrm{.}0m$ long and each has an $EI=4\mathrm{.}5{10}^{6}N-m^2.$ The structure has a viscous damping $($