# Stokes law

1. Feb 1, 2009

### LaurenG

Hello all.

I'm investigating a little bit about stokes law in order to understand the settling velocity of falling particles and on the net i encountered with 2 different formulas and i simply can't find the reason why they are different. every formula gives me a different answer.
The 2 formulas are :
1. Vt=gd^2(Pp-Pm)/18u -
2. V=2/9*d^2*g*(Pp-Pm)/u -

Any idea why they are different ?
Thanks.

Last edited: Feb 1, 2009
2. Feb 1, 2009

d=2R

3. Feb 2, 2009

### LaurenG

Silly me, i knew it's something stupid.
Thanks :)