Perpetual motion

[Classact]

OK here is the question, why does the earth spin with such accuracy and what makes it spin? Why couldn't this perpetual motion be recreated in a smaller scale to produce energy?

Here is the best answer I have so far. http://www.newton.dep.anl.gov/newton...ron/AST050.HTM

[manu1959]

you would need to create a frictionless vacuum for the perpetual engine to spin in.....take a physics class it is one of the experiments....or at least it was when i went to university 25 years ago....

[Classact]

you would need to create a frictionless vacuum for the perpetual engine to spin in.....take a physics class it is one of the experiments....or at least it was when i went to university 25 years ago....

With that in mind, couldn't a large generator be placed in space with an exact earth speed orbit that could generate power and change it into a laser beam directed to an earth receiver dish? I guess planes and birds would be toast that crossed the path but it seems like a green power machine that would create power for a single investment. I read that the earth rotation would speed up if it weren't for ocean tides, so if that is true then the generator could be controlled by a computer to control speed with resistance like a rheostat.

[Hobbit]

You're forgetting the law of conservation of energy. If you set an object to spin in a frictionless vacuum with no opposing forces, it will spin forever, but to get it to produce, say, electricity, you must remove energy from the system, thus causing it to slow down.

The spin of the Earth isn't generating any power, so, by Newton's first law, it will continue to spin until such time as it is acted on by an outside force. If we attached a generator to its axis, we'd get quite a bit of electricity up until the day the Earth stopped spinning.

The reason tides affect the spin of the Earth has to do with torque equations. I can't remember torque right now, but the energy of a spinning system is directly proportional to its radius and revolutions per unit time. The tides increase the radius of the Earth. Since energy remains constant, this has a corresponding decrease in the rate of rotation. However, when the tide shifts, the changes cancel each other out and are too small to be noticed. In order to see this principle in action, there are 2 things you can do. The first is to sit in a rotating chair with one weight in each hand. Spread your arms out and then get a friend to start you spinning (or use your foot). Once you are spinning, pull your arms in and you'll notice that you start spinning 'faster.' The other way involves watching figure skating. Watch when one of the skaters is spinning with her leg outstretched, then watch as she pulls it in. She starts spinning really fast.

[Monkeybone]

if the pic doesn't show up http://simulatedcomicproduct.com/200.../zimmer-wheel/

[Hagbard Celine]

If you built a ring that spanned the perimeter of the Earth it could be engineered to spin along with the Earth using the Earth's own gravity. The spinning movement of the inner ring could be converted into energy. Probably enough to power the entire planet. It would be like using the Earth's own rotation to generate power. People could live and work on it. It could have vast hydroponic farms to produce food for the planet. Sounds like a good Will Smith movie.