Electron travel in a wire; distance

[megr_ftw]

Homework Statement

The starter motor of a car engine draws a current of 140 A from the battery. The copper wire to the motor is 5.0 mm in diameter and 1.2 m long. The starter motor runs for 0.95 s until the car engine starts.

How far does an electron travel along the wire while the starter motor is on?

Homework Equations

drift velocity= (j) / (en)
j= current density, e=elementary charge, n=concentration of gases in material(given in book)

j= I/A

The Attempt at a Solution

I found the charge that passes through the starter motor to be 133 Coulombs. Am I suppose to incorporate the equation for drift velocity in order to find the distance?

 

[megr_ftw]

and I actually just found the current density to be 7130141.45 A/m^2 using the second equation.
now, how am I suppose to go from this to the distance the electron travels after 0.95 seconds??

 

[physeven]

you can use simple mechanics. consider the electron a point charge moving with a uniform drift velocity and i presume you will get the solution. just don't expect me to get it for you though.