Can somebody explain the force opposing gravity when you drop a magnet in a copper tube?

Question

Note that the magnet has its South pole at the bottom

Answer 1

The magnetic field of the magnet moves the electrons in the copper tube producing an electric current that creates a magnetic field that opposes that of the magnet, slowing its descent. This property of opposing forces produces an effect called "hysteresis" or "lag"

Dan the net electrical force in the tube would be zero. The energy would be dispersed in the form of heat and light.

Answer 2

Dan is right. The magnetic moving through the tube induces current to flow in the tube. This moving current produces a magnetic field that opposes the motion of the magnet and so slows the magnet down. The exact same kind of thing happens in a generator, where your spinning magnets around inside of coils of wire. It takes energy to turn the rotor in a generator because the magnets are exerting forces on the electrons in the coils and there is a counter magnetic field pushing back on the magnets.

Answer 3

A magnet dropped in a vertical metallic tube will fall slower than if dropped in a non-conducting tube. This is because the magnetic field that surrounds the magnet will induce eddy currents in the metal as the magnet moves downward. The production of eddy currents requires energy and the only source of energy in the system is the kinetic energy of the moving magnet.

Bottom line some of the kinetic energy of the magnet becomes an electric current in the tube and this involves a transference of energy.