A particle having a charge $q=1C$  and mass $m=0.5kg$ is projected on a rough horizontal plane $(x,y)$  from a point  $(15m,0,0)$ with a initial velocity  $\overrightarrow{v}=20\hat{j} m/s$.  In space a uniform electric field  $\overrightarrow{E}=25(-\widehat{k}) V/m$ and magnetic field $\overrightarrow{B}=10(-\widehat{k}) T$ . The acceleration due to gravity  $g=10m\text{\hspace{0.17em}/}{\sec }^2$ and co–efficient of friction  $\mu =0.5$. The particle moves on a spiral path and stops. Total time of journey is $\frac{y}{3}\sec$. Find  $y$.