Moving magnet generates electric field (electromagnetic induction, like a bike dynamo)
Electric field drives current in the copper (assuming there is copper nearby)
Current in the copper makes another magnetic field (i.e. it’s an electromagnet)
This second magnetic field acts back on the falling magnet, slowing it down (like a bar magnet would if only we were clever enough to put the bar magnet in exactly the right place).
The current also heats up the copper, the energy required to do that being the kinetic energy that the falling magnet would have acquired if the copper tube hadn’t slowed it down.
As for why there’s no such thing as magnetism … that’s relativity, so harder (but it’s only special relativity, so not as hard as it could have been).
Yup, like water. Diamagnetic stuff is repelled out of regions of strong magnetic field and so it can be levitated if you can make the field strong enough. Frog is mostly water. Here is some frog inside a very, very strong electromagnet
Count yourself lucky (see above). I think the frog seemed to survive fine. Unfortunately they couldn’t ask it what it felt like. I imagine it might be a bit of a bugger if you’ve got metal tooth fillings (magnets induce electricity).
The guy I knew there had I don’t now how many layers of management above him, extending right to the very top of a huge US aerospace multinational. He said that up to that point the interest in his work had petered out in any real sense just a few layers up. He was making the organisation proper money, and promising to make them more in the future (aircraft engine turbine blades need re-working sometimes and they are surprisingly expensive). But when word got out about the golf clubs he started to get visits from people so senior that they’d never even visited the plant, let alone my mate’s lab. And they weren’t interested in possible business developments - it seems the golf authorities are pretty quick to ban any technological process that gives some players an advantage over others. No. They just wanted to get some of these clubs for their own personal use. Which, of course, they did.
Very true, it makes sense in a way Golf courses were built all over the world with certain yardages in mind for par 4s and 5s etc. If the equipment gets too advanced the courses are no longer a challenge so it is easier to limit the tech than try and alter thousands of courses.
A similar thing happened in Athletics with the Javelin, athletes were starting to throw it out of the arena, as they couldn’t rebuild every stadium they changed the rules. In 1984 the world record was over 100 metres so they changed the spec to get it back down to 85 metres. By 1991 it was back up to 98 metres so they changed the rules again. otherwise sooner or later a spectator was going to be speared!
What could be a better use of technology!
