perfect- are you DC bound?

Great post. Relief from indigestion of D.C.

Pretty fun, huh

Now you've got me cruising all over this Quora thing...Good grief...Like crack for the inquisitive.

Impressive.

and you can use these gifs on your posts here and elsewhere to exclamation. thanks

Great stuff all in one collection. I've seen parts before. Fabulous what people can do with nature. Science rocks! Thanks for posting. A welcome change from political sludge.

wow. thanks, thor. your turn to post something cool ;)

I must be a geek too. I spent way to much time at that link.

You can readily feel this is you wave a Neodymium magnet near/across a thick metal plate (non magnetic plate or the force of attraction will eclipse this effect). The force comes from eddy currents produced in the metal plate or copper tube. These Eddy currents interact with the magnetic field to product force. This is how an induction motor works. Another way to look at it is there is a loss from the eddy currents conducting through the resistance of the metal. The force you feel is the mechanical input of this electrical loss (conservation of energy).

I have some magnets and aluminum plates in my office if anyone wants to see. :)

BTW the Disney "Rockin Roller Coaster" uses this effect. It has stationary linear motors, with magnets on the trolley under the cart for propulsion. These motors drive the trolley+cart from 0-55mph before the trolley disengages and the cart carries the screaming passengers up the first ramp. The trolley is stopped simply with aluminum plates in place of the motor stators at that point along the path. These plates that interact with the magnets on the trolly, like the pipe in the video. Watching it, you would swear there are mechanical brakes, stopping a 1,500 lb trolly from 55 mph in like 10 feet!

Yes, I am a geek.

I like the slinky. It's so counter-intuitive that the center of mass is accelerating toward the bottom ring at g, yet the bottom ring is not accelerating!

cool. :)

ok ;)

Electro-magnetism--A moving magnetic field creates an electric field in the copper pipe creating a current--The current creates a magnetic field affecting the magnetic field of the magnet.

yes, it's not as weak as you'd think since it slows magnet.

What a great find. Thanks for posting this. I loved the slinky drop.