$($b$)$ The $8kg$ body shown in Fig. $5$ is moved $0\mathrm{.}2m$ to the right of the equilibrium position and released from rest at time $t=0.$ Determine its displacement at time $t=2$ seconds. The vicious damping coefficient $c$ is $20N-\frac{s}{m}$ and the spring stiffness $k$ is $32\frac{N}{m}.$

Fig. $5$