A bullet is moving horizontally with certain velocity. It pierces two paper discs rotating coaxially with angular speed $\omega$ separated by a distance $l$. If the hole made by bullet on second disc is shifted by an angle $\theta$ with respect to the first, find velocity of bullet.

A particle is kept fixed on a uniformly rotating turn-table. As seen from the ground, the particle goes in a circle and its speed and acceleration are $10 \mathrm{cm} {\mathrm{s}}^{-1}$ and $10 \mathrm{cm} {\mathrm{s}}^{-2}$ respectively. The particle is now shifted to a new position to make the radius double of the original value. The new values of the speed and acceleration will respectively, be