A particle is projected up an inclined plane with initial speed $v=20 m/s$ at an angle $\theta=30 ^{\circ}$, with the plane. The component of its velocity perpendicular to plane when it strikes the plane is

Question

\[(a)\;10 \sqrt 3 m/s \quad (b)\;10 m/s \quad (c)\;5 \sqrt 3 m/s \quad (d)\; data \; insufficient \]