A bed of spherical glass beads (density 3000 kg/m3 diameter 1 mm, bed porosity 0.5) is to be fluidized by a liquid of density 1000 kg/m3 and viscosity 0.1 Pa.s. Assume that the Reynolds number based on particle diameter is very small compared to one. If g = 10 m/s2 then the minimum velocity (in m/s) required to fluidize the bed is