Consider the system shown in Figure $1,$ where $m=2kg,B=$

$4N-\frac{s}{m},$ and $k=20\frac{N}{m}.$ Assume that $x(0)=0\mathrm{.}1m$

and $x^{}(0)=0.$ The displacement $x(t)$ is measured from the

equilibrium position. Derive a mathematical model of the

system using energy principles and find $x(t)$ as a function of

time $t.$