What is an example of something that has perpetual motion?

Answer 1

Perpetual Motion, long-held concept of a system that could provide useful work indefinitely, once set in motion. Such a system is not in accord with the fundamental laws of physics. Any system will run down when left to itself, through various forms of attrition. it has connection with Thermodynamics.
Classical thermodynamics is concerned with the observed properties of bulk matter and is independent of any microscopic model of matter. It establishes relations between bulk properties, so that measurements of one may be used to infer the value of another. Statistical thermodynamics acknowledges the atomic nature of matter, and is used to express bulk thermodynamic properties to the average behaviour of large assemblies of atoms. Thus, statistical thermodynamics (which is also known as statistical mechanics) provides the link between the properties of individual atoms measured spectroscopically and bulk properties.

Answer 2

Randy is wrong about the orbits of planets.

Planetary orbits do decay, given enough time. The most obvious example is the moon's orbit. The moon has slowed in its orbit because of the tides. We know this because of the evidence of ancient sea beds in places like South Africa, which show that high tides were once 9 hours apart, instead of 12 hours 25 minutes..

Because of the slowing, the moon's speed has slowed. Of course, when an orbit slows, the planet moves farther from the center, not closer. It would have to speed up to get closer.

All the planets will continue to drive marginally further from the sun as tidal forces slow them down ever so gradually. It just goes to show, however, that there cannot be such a thing as perpetual motion, even in space.

Answer 3

If you look at the quantum particle level you can see something that approaches perpetual motion. If you define perpetual motion as "a motion for a period of time where there is no loss of speed"

Answer 4

nothing, perpetual motion means something is moving all the time with no outside force being exerted. If you were to push a swing and it swang back and forth forever, then it would be perpetualy in motion. But gravity and friction will slow and then finally stop the swing's motion. Gravity and friction stops everything unless there is some sort of force applied.

Answer 5

Planets in their orbit around the sun.