As per the given figure, a small ball $P$ slides down the quadrant of a circle and hits the other ball $\mathrm{Q}$ of equal mass which is initially at rest. Neglecting the effect of friction and assume the collision to be elastic, the velocity of ball $\mathrm{Q}$ after collision will be $\left(\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2\right)$ <br>