Consider a cylindrical tank of radius 1 m is filled with water. The top surface of water is at 15 m from the bottom of the cylinder. There is a hole on the wall of cylinder at a height of 5 m from the bottom. A force of $5 \times 10^5 \mathrm{~N}$ is applied an the top surface of water using a piston. The speed of efflux from the hole will be : (given atmospheric pressure $\mathrm{P}_{\mathrm{A}}=1.01 \times 10^5 \mathrm{~Pa}$, density of water $\rho_{\mathrm{w}}=1000 \mathrm{~kg} / \mathrm{m}^3$ and gravitational acceleration $\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$ )