A frictionless circular piston of area  and mass 100 kg sinks into a cylindrical container of the same area filled with water of density  as shown in the figure. The container has a hole of area  at the bottom that is open to the atmosphere. Assuming there is no leakage from the edges of the piston and considering water to be incompressible, the magnitude of the piston velocity (in m/s) at the instant shown is __________ (correct to two decimal places).