Three different sized fly ash particles settle through air. You are asked to calculate

the particle terminal velocity and determine how far each will fall in $30$ s$.$ Also

calculate the size of a fly ash particle that will settle with a velocity of $1\mathrm{.}384$ ft$/$s$.$

Assume the particles are spherical. Data are provided below.

Fly ash particle diameters $=0\mathrm{.}4,40,400$um$,$ Air temperature and pressure $=2380$F$,1$ atm, Specific gravity of fly ash $=2\mathrm{.}31$