A block of mass $0.1 \mathrm{kg}$ is attached to a cord passing through a hole in a horizontal frictionless horizontal surface as shown in the figure. The block is originally revolving at a distance of $0.4 \mathrm{m}$ from the hole, with an angular velocity of $2 \mathrm{rad} {\mathrm{s}}^{-1}$ . The cord is then pulled from below, shortening the radius of the circle in which the block revolves to $0.2 \mathrm{m}$. Considering the block to be point mass, calculate the new angular velocity (in $\mathrm{rad} {\mathrm{s}}^{-1}$).