Assume a point$-$source particulate emission having an effective stack height of $200$ feet. The plume contains particles having a density of $2\mathrm{.}3\frac{g}{c}{m}^3,$ the stack$-$gas temperature is

$80F,$ and the wind speed is constant at $5mph.$ Assuming the terrain is flat, Determine the Stokes' settling velocity in $\frac{m}{s}$ that a $10m$ particle will travel with.

The viscosity and density for air are assumed as $6\mathrm{.}66{10}^{-2}k\frac{g}{m}.hr$ and $0\mathrm{.}0012\frac{g}{c}{m}^2.$

$1\mathrm{.}69{10}^{-1}$

$1\mathrm{.}69{10}^{-3}$

$6\mathrm{.}67{10}^{-3}$

$6\mathrm{.}67{10}^{-1}$