Question 28: Magnetism and Matter

Question

A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will

Accepted Answer

When a bar magnet is released from rest along the axis of a very long vertical copper tube, it will move down with an almost constant speed after some time.
As the magnet falls, it moves through the copper tube, inducing eddy currents in the tube. These eddy currents, in turn, create an opposing magnetic field that opposes the motion of the magnet. The opposing force generated by the eddy currents acts as a damping force, which slows down the magnet's acceleration. Eventually, the magnet reaches a terminal velocity, at which point the gravitational force pulling the magnet downward is balanced by the opposing force from the eddy currents.
At this terminal velocity, the magnet moves down with an almost constant speed.

Answer

move down with almost constant speed

Answer

move down with an acceleration equal to $$\mathrm{g}$$

Answer

move down with an acceleration greater than $$\mathrm{g}$$

Answer

oscillate inside the tube

Magnetism and Matter

A bar magnet is released from rest along the axis of a very long vertical copper tube. After some time the magnet will

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