Electron travel in a wire; distance

AI Thread Summary
To determine how far an electron travels in the wire while the starter motor operates, the drift velocity must be calculated using the current density and electron concentration. The current density was found to be 7130141.45 A/m², and the total charge passing through the motor is 133 Coulombs over 0.95 seconds. By applying the drift velocity formula, the distance traveled by the electrons can be computed. The key equations involve current density (j = I/A) and drift velocity (v_d = j/(en)). The final calculation will yield the distance traveled by an electron during the motor's operation.
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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?
 
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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??
 
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