A particle ( $m=1 \mathrm{~kg}$ ) slides down a frictionless track (AOC) starting from rest at a point A (height 2 $\mathrm{m})$. After reaching C , the particle continues to move freely in air as a projectile. When it reaching its highest point $P$ (height 1 m ), the kinetic energy of the particle (in J ) is : (figure drawn is schematic and not to scale; take $\mathrm{g}=10 \mathrm{~ms}^{-2}$ )