A particle of mass 2 kg is moving on a straight line under the action of force F=(8-2x)N. The particle is released at rest from x=6m for the subsequent motion. Select the correct options:

Equilibrium :  F=8-2x=0$\Rightarrow$x=4
As particle is at rest (Exhenete position) at 6m
Amplitude is 6-4=2m
Now $\mathrm{T}=2\mathrm{\pi }\sqrt{\frac{\mathrm{m}}{\mathrm{k}}}=2\mathrm{\pi }\sqrt{\frac{2}{2}}=2\mathrm{\pi s}$
Time to move from 2m (Exhenete) to 4m (mean) 
$\frac{\mathrm{\pi }}{4}=\frac{\mathrm{\pi }}{2}\mathrm{s}$
Energy $=\frac{1}{2}{\mathrm{mA}}^2{\mathrm{\omega }}^2=\frac{1}{2}\times 2\times 2^2\times 1^2=4\mathrm{J}$