# Stokes law - Settling velocity and rate

by Maharg
Tags: settling stokes
 P: 30 I think you forgot to square one of the terms which is why you are missing an m. I assumed the settling rate was just the previous number * the concentration, although you are right, the book did not discuss it! ("Environmental Chemistry: a global perspective" by Gary w vanLoon and Stephen J. Duffy is full of errors and questions which does not reflect the material covered.) Anyway, this was code to solve the problem: #!/usr/bin/env python from __future__ import division from scipy import pi p_p=1.8*10**6 #g/mL d_p=13e-06 #m C=1.016 p_a=1.2e03 #g/m^3 eta=1.2e-02 #g/ms g=9.81 #m/s/s N= 800 #ug/m^3 Vt=(p_p-p_a)*C*g*d_p**2/(18*eta) print 'Problem 6.4' print '===========' print 'Settling velocity = ' + str(Vt) + ' m/s =' +str(Vt*100) + ' cm/s' print 'Settling rate = ' + str(Vt*N) + ' ug/m^2/s'