Cosmic Rebels Stokes

 A form of the Stokes' Law equation for the terminal velocity of a spherical particle in a viscous fluid

. 

Based on the structure, the expression can be rewritten as: 

$v=\frac{2}{9}\frac{({\rho }_p-{\rho }_f)g{r}^2}{\eta }$

 where: 

• 

  $v$
  is the terminal velocity.
• 

  ${\rho }_p$
  is the density of the particle.
• 

  ${\rho }_f$
  is the density of the fluid.
• 

  $g$
  is the acceleration due to gravity.
• 

  $r$
  is the radius of the spherical particle.
• 

  $\eta$
  is the dynamic viscosity of the fluid. This equation calculates the terminal velocity (or settling velocity) of a small, spherical particle falling through a viscous fluid when the drag force and the buoyancy force are balanced with the gravitational force acting on the particle.