The pressure of  water inside a closed pipe is $3\times {10}^5\mathrm{N}/{\mathrm{m}}^2$. This pressure reduces $2\times {10}^5\mathrm{N}/{\mathrm{m}}^2$ on opening the valve of the pipe. Calculate the speed of water flowing through the pipe. Density of water $=1000 \mathrm{kg}/{\mathrm{m}}^3$