A block B of mass 0.5 kg moving, on a horizontal frictionless table...

A block B of mass 0.5 kg moving, on a horizontal frictionless table at $2.0 \mathrm{~ms}^{-1}$, collides with a massless pan P (at origin O ) and sticks to it. The pan is connected at the end of a horizontal un-stretched (relaxed) spring of force constant $\mathrm{K}=32 \mathrm{Nm}^{-1}$ as shown in figure. After the block collides, the displacement $x(t)$ of the block as a function of time $t$ is given by