We will use air at $20C$ to fluidize a bed of spherical particles of diameter $4\mathrm{.}9mm$ and density $3158k\frac{g}{m}3.$ We find that at the minimum fluidization velocity our bed has a height of $1\mathrm{.}2m$ and a void fraction of $0\mathrm{.}42.$ At minimum fluidization what is the frictional pressure drop $(Pa)$ through the bed? Do not enter the units in the answer box.