"I could do this all day. It's so cool".
Am I correct in assuming that if he did it all day, it would not actually be so cool, as the copper tube would be heated up by the induced currents?
Am I correct in assuming that if he did it all day, it would not actually be so cool, as the copper tube would be heated up by the induced currents?
We don't see the tube, but assume that it is 1m long. The experimenter picks drops the 100g magnet into the tube once per second and that it has zero velocity at the tube exit. i.e. initial and final kinetic energy is zero, but the experimenter keeps inputting gravitational potential energy, all of which gets converted to heat.
Power = m * g * h / t = 0.1 * 10 * 1 / 1 = 1 W.
So, dropping a magnet every second generates 1 W of heat, which is virtually nothing.
This result is logical. The only energy input is the experimenter repeatedly moving the magnet from the bottom to the top of the pipe, and this simple movement probably won't tire him out. He could, indeed, do it all day.
I would be interested in hearing what would happen if the pipe was a superconductor, though - would the induced current be so strong that the magnet wouldn't drop at all?
http://www.physorg.com/news/2011-10-quantum-levitating-video...
Only somewhat; it's a different set-up, of course.
Diamagnetic materials create an equal field to what they are exposed to... Causing repulsion. In the case of superconducting, the field generated is very strong and why we can levitate any old magnet over a superconductor.
Levitating a frog (mostly water right?) takes some incredibly strong fields..... Liquid cooled bitter magnets etc....
Side note - rare earth supermagets are toxic. When they shatter, you dont want to ingest any of the bits/dust