Terminal speed with linear drag

1. Sep 24, 2014

PsychonautQQ

1. The problem statement, all variables and given/known data
An object moves through a liquid horizontally against a linear drag force given by F = -cv
What is the terminal velocity? Initial Velocity is V_0

2. Relevant equations
F=ma

3. The attempt at a solution

m(dv/dt) = -cv
-->
(dv/v) = (-c/m)dt
ln(vf/v0) = -ct/m
vf=v0*e^(-ct/m)

which says that as time goes to infinity that vf will equal v0 but that doesn't make any sense physically... what did I do wrong here?

2. Sep 24, 2014

vela

Staff Emeritus
Take the limit incorrectly? $V_f$ approaches 0 as $t \to \infty$, no?