Question $3$:

$(8$ points$)$

A bed consists of uniform spherical particles of diameter $3mm$ and density $4200k\frac{g}{m^3}.$ What will be the minimum fluidizing velocity in a liquid of viscosity $3mN\frac{s}{m^2}$ and density $1100k\frac{g}{m^3}($use Ergun equation$)?$