Arturo O. answered • 04/12/18

Experienced Physics Teacher for Physics Tutoring

I suspect that the coefficient of 0.23 is really some constant that has a value of 0.23 in SI units, instead of a pure number. If so, its units must be ms/kg so that when multiplied by kg/s

^{2}, you get m/s.Then

v

_{f}= k(ρ_{s }- ρ_{o})gr^{2}where

k = 0.23 ms/kg

It probably comes from the slope of a linear plot of measured terminal speed vs. measured (ρ

_{s}- ρ_{o})gr^{2}. Does this sound reasonable?