ABSTRACT
The resistance caused by the air to the drop in its direction of motion caused by this viscous resistance is:
FStokes = 6phrv (3.2)
where v = drop velocity relative to air r = drop radius
h = viscosity of air (182.7 ¥ 10-6 gram/cm-sec at standard temperature and pressure)
The origin of this force is from the viscosity of the medium, in this case, air. Viscosity is roughly defined as the resistance of a medium to a change in its shape. The energy needed to orderly deform a viscous medium so that an object can pass through it (laminar flow) is the source of the Stokes resistance.
