Magnetism & Engineering

[VansenS]

Can someone explain this video:



If I put this together myself should I expect it work or is that some hoax? If that's just a normal use of magnetism, then where can I read more about the principles behind it? Do these magnets get weaker over time?

 

[Redbelly98]

From a recent comment on the video:

If you notice at 1:57,he is moving the handheld magnets.If you can understand this, how he is able to keep this working is due to the motion of his hand affecting the position of the hand-held magnet.

In other words, by moving the hand-held magnet he does work (i.e. supplies energy) on the system.

If you do build this, please post back and let us know what you find out.

 

[vk6kro]

It looked like the motor was turning pretty fast, so maybe they stopped the filming and inserted a battery in the wiring. So it would be a hoax. Don't waste your time with it.

You could make a synchronous motor like that, but you couldn't control the magnet accurately enough with your hand.
If all the magnets in the rotor were mounted with north poles facing out then you could attract each one with a south pole and then repel it with a north pole to keep the rotor turning.

 

[BenchTop]

If you start out with a rapidly spinning wheel and videorecord it as the dynamic brake of the light slows it to a stop while you hold a carrot nearby, then you can reverse the clip and post it on youtube and get a few people to try wiggling a magic carrot around...lol.
Sometimes the object is selling them the magic carrots to play with.