- #1
Eric Wright
- 16
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Homework Statement
If we drop a bar magnet down a copper tube, it will travel down very slowly. If we now cut vertical slits in the copper tube, will the magnet travel down faster or slower as compared to the original problem?
Homework Equations
[tex] \int \vec E \cdot d \vec l = -\frac{d \Phi}{dt} [/tex]
[tex] V = Q/C [/tex]
The Attempt at a Solution
As a model, I imagine horizontal strips of the copper tube located above and below the location of the magnet. If we look at a strip below the magnet, we can view the strip as a circuit with several capacitors. Given the same EMF, a circuit with capacitors will have a lower current as compared to a similar circuit without capacitors. The force on the magnet is proportional to the current in the strips, so there will be less force if we cut vertical slits in the tube. Thus the magnet will drop more quickly.
Is my model/logic correct here? Any comments would be great!
Thanks,
Eric