- #1
tamtam402
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Has anyone ever considered this issue with magnet falling in copper tube??
I must explain why a magnet falling in a copper tube slows down.
F = B^qv
However, I must *explain* this, I don't have to calculate anything
I understand that the magnet can fall with it's south pole or north pole first, and it still slows down. I understand the direction of the current formed by induction in the copper tube. It's easy to see (I attached a drawing) that the north pole of the magnet faces the north pole of the current caused in the copper tube.
What I don't understand is the stuff happening ABOVE the tube. The way I see it, the south pole will get further and further away from a given point of the tube. Moving a south pole away from a conductor is the same thing as moving a north pole closer to a conductor. That means the current above and below will be going in the same direction. That also means the SOUTH pole of the upper magnetic field will face the SOUTH pole of the magnet.
If the bottom north/north poles are facing each other, I understand why the magnet slows down. However, the south/south poles are facing each other once the magnet has passed a given point of the tube. Why is the magnet slowing down then? Shouldn't it get pushed down by the south/south poles as much as it gets slowed down by the bottom north/north ones?
***NOTE*** I've seen a few drawings while browsing the internet with the current above the magnet going in the opposite direction from the bottom one, which means the upper part would have a north/south pole facing, also slowing down the magnet. I don't understand how the current can go in that direction though...??!
Homework Statement
I must explain why a magnet falling in a copper tube slows down.
Homework Equations
F = B^qv
However, I must *explain* this, I don't have to calculate anything
The Attempt at a Solution
I understand that the magnet can fall with it's south pole or north pole first, and it still slows down. I understand the direction of the current formed by induction in the copper tube. It's easy to see (I attached a drawing) that the north pole of the magnet faces the north pole of the current caused in the copper tube.
What I don't understand is the stuff happening ABOVE the tube. The way I see it, the south pole will get further and further away from a given point of the tube. Moving a south pole away from a conductor is the same thing as moving a north pole closer to a conductor. That means the current above and below will be going in the same direction. That also means the SOUTH pole of the upper magnetic field will face the SOUTH pole of the magnet.
If the bottom north/north poles are facing each other, I understand why the magnet slows down. However, the south/south poles are facing each other once the magnet has passed a given point of the tube. Why is the magnet slowing down then? Shouldn't it get pushed down by the south/south poles as much as it gets slowed down by the bottom north/north ones?
***NOTE*** I've seen a few drawings while browsing the internet with the current above the magnet going in the opposite direction from the bottom one, which means the upper part would have a north/south pole facing, also slowing down the magnet. I don't understand how the current can go in that direction though...??!