Eli5: why cant we use magnets to make an infinitely spinning thing to get infinite energy

Question

-english is not my first language-

Edit: alot of people think im referring to motors or generators or some sorts. But I mean something like this:

https://i.ytimg.com/vi/BSdSDfOWbNs/maxresdefault.jpg

I know its probably fake and not possible but I want to know why and how

In: 0

Answer 1

There is an experimental coalmine truck. It is electric and drives empty uphill to the mine to get loaded. Once its full it a dynamo is added to harvest energy whil it deives downhill. All the extra weight makes the creation of energy possible. This fills the batterys for the drive back up to the mine.