Monday, August 5, 2013

Magnetic Perpetuum Mobile



Is this a Magnetic Perpetuum Mobile?




The law of conservation of energy forbids perpetual motion. On the other hand, the small magnets in this image seem to be attracted / repelled by the large magnet, producing motion. As a child, I imagined this machine, and for a while I was perplexed, since on the one hand I knew it can't move forever, because it would break conservation of energy, but on the other hand, it is not that obvious what exactly happens that makes it stop.

2 comments:

Elie Nasrallah said...

Very good paradox but the explanation is too concise.

Cristi Stoica said...

Thanks. It is indeed concise. I posted a slightly longer explanation at Physics Stack Exchange.