Properties of Matter Part 1

Consider a water tank as shown in the figure. It's cross-sectional area is 0.4m2. The tank has an opening B near the bottom whose cross-section area is 1cm2. A load of 24kg is applied on the water at the top when the height of the water level is 40cm above the bottom, the velocity of water coming out the opening B is vms−1. The value of v, to the nearest integer, is (Take value of g to be 10ms−2 )