Physics
posted by sied .
We release an oil drop of radius r in air. The density of the oil is 640 kg/m . c_1 and c_2 for 1 atmosphere air at 20 C are 2.20* 10 ^4 (kg/m)/sec and 0.81 kg/m , respectively.
How small should the oil drop be so that the drag force is dominated by the linear term in the speed (in lectures we called this Regime I). In this regime, the terminal velocity is m*g/(c_1*r) . [ m is the mass of the drop].
r<<?

r^3=(3*C_1^2)/4*pi*d*C_2*g
do the cubic root
d=density 
its not working ..! :(