2 magnets falling, one through a metal ring, which is faster

[moenste]

Homework Statement

Two small bar magnets X and Y are released from rest at the same height above the ground. X falls directly to the ground, but Y passes through a metal right which is fixed with its plane horizontal. Does X reach the ground: (A) at the same time as Y, (B) before Y, (C) after Y? Explain your answer.

2. The attempt at a solution
I think that X will reach the ground before Y because the metal ring will slow down the Y magnet. The Y magnet will be retarded before entering the ring and after passing it. But I don't know whether this is right and what's the cause of it. Electromagnetic induction? The ring should magnetize the magnet on entering and should keep it when it passes through it as I see it.

 

[phoenix95]

I think that X will reach the ground before Y because the metal ring will slow down the Y magnet.

Correct.

The Y magnet will be retarded before entering the ring and after passing it.

Before entering and after passing? Nope.

But I don't know whether this is right and what's the cause of it. Electromagnetic induction?

Correct. Lenz's law is the apt way to put it. When the magnet passes through the metal tube, the magnetic flux relative to the tube changes. The changing flux produces current in the metal tube, in such a way that it opposes the motion of the magnet.

Here is a link if you are interested...

 

[tony873004]

If you don't want to run down to the hardware store to buy some pipe, a roll of aluminum foil works great for this experiment.