We have a packed bed filled with spheres of density $7882k\frac{g}{m}3$ and diameter $18mm.$ The void fraction at mimimum fluidization is $0\mathrm{.}46.$ We will fluidize the particles with air at $20C.$ The average pressure in the bed is $1\mathrm{.}1$ ATM. The viscosity of the air can still be estimated as $0\mathrm{.}018cP.$ What is the minimum fluidization velocity $(\frac{m}{s})?$