perpetual motion

[Physics confusion]

HI,
Can anyone describe in terms of physics what perpetual motion is and also zero point energy. thanks.

 

[wlminex]

Not in terms of formal 'physics' - I'll try the pea brain, non-scientist, fringe-guy, crank approach first (but probably will get flack from self-professed real 'research scientists' on this forum):

Perpetual Motion: A process that does work without depleting its energy source. Much like using magnetism to 'perpetually' suspend a magnetic mass in a gravity field.

Zero Point Energy: Useful energy (does work) extracted from a matrix that we cannot otherwise detect. Similar to over-unity devices that produce more energy than they consume.

wlminex

 

[prometheus]

Yeesh. I can't leave this now...

A perpetual motion machine is one that produces more useful work than it consumes. It is impossible and is ruled out by the second law of thermodynamics.

wlminex attempt at an example is wrong because gravity is a conservative field, so it only requires work to move from a point of low gravitational potential to a point of higher potential. Staying at the same potential (like a magnet sticking to a fridge) requires no work.

Zero point energy is the statement that, due to the laws of quantum mechanics, the lowest possible energy state of a system is not zero, but some finite number greater than zero. Take a look at the infinite square potential well in quantum mechanics and you will see that it is not possible to have a zero energy state.

wlminex's answer to this is gibberish.

 

[wlminex]

Prometheus #3:

. . . So, if an iron ball is rolling down a hill under the influence of gravity, and the ball passes beneath a large magnet suspended above the ball's rolling path, the suspended magnet will not retard 'gravity' from doing it's work (i.e., rolling the iron ball down the hill)? Sounds like 'work' is being performed somehow, by something. Like converting kinetic energy to potential energy, perhaps? Or . . . . OMG!! . . . creating an antigravity situation.

wlminex

 

[prometheus]

A force does work if it induces an acceleration. Gravity is doing work accelerating the ball. When the magnet decelerates the ball it is doing work. When the ball stops and gravity and the magnet are in equilibrium, no work is being done.

 

[wlminex]

Prometheus #5:

Q.E.D.! . . . so when I use my magnetic trailer hitch, no no work is being done during a trip from New Mexico back to Missouri when I tow the trailer . . . only when I accelerate, slow-down, coast downhill with gravity assist, or I accelerate (uphill with gravity resist). The magnetic coupler is static and plays no role whatsoever! . . . . . Oh . . . I've seen the light!! . . . ergo . . . . my electric fan does no work while its running (at constant velocity) . . only when it accelerates when initially switched-on - COOL!

wlminex

 

[prometheus]

If your car and trailer combination was frictionless then yes, travelling at a constant speed would require no energy. If you're talking about the work that gravity is doing on your car then why the hell would you do that?

Your electric fan on the other hand is accelerating, even when it's going at a constant angular velocity.

I think you're trolling me now. My view of human nature would be severely harmed if you were really as dumb as you seem to be.

 

[wlminex]

Prometheus #7:

So . . . if I drive continually around in a circle, I (and the magnetic coupler) are constantly accelerating due to the system angular momentum! WOW! . . . also, I LOVE fishing (trolling) . . . get out of the box on occasion - that's where new ideas usually spring forth . . . . and remember something I posted elsewhere:

"Those best bear reproof, who merit praise!"

Sorry if I have harmed your view of human nature!

wlminex (da' dummy)

 

[James R]

Perpetual Motion: A process that does work without depleting its energy source. Much like using magnetism to 'perpetually' suspend a magnetic mass in a gravity field.

A magnet that is suspended in space is not in motion. Therefore, that cannot be an example of perpetual motion.

Zero Point Energy: Useful energy (does work) extracted from a matrix that we cannot otherwise detect. Similar to over-unity devices that produce more energy than they consume.

Over-unity devices do not exist. Zero-point energy does.

A perpetual motion machine is one that produces more useful work than it consumes. It is impossible and is ruled out by the second law of thermodynamics.

More precisely, a perpetual motion machine of the first kind violates the first law of thermodynamics (e.g. by creating useful work out of nothing, or puttiing out more energy than it takes in). A perpetual motion machine of the second kind violates the second law (e.g. by completely converting heat into useful work).

Zero point energy is the statement that, due to the laws of quantum mechanics, the lowest possible energy state of a system is not zero, but some finite number greater than zero.

This is correct.

wlminex's answer to this is gibberish.

Most of wlminex's posts are gibberish.

so when I use my magnetic trailer hitch, no no work is being done during a trip from New Mexico back to Missouri when I tow the trailer . . . only when I accelerate, slow-down, coast downhill with gravity assist, or I accelerate (uphill with gravity resist). The magnetic coupler is static and plays no role whatsoever!

No. Every time the magnetic coupler exerts a force on the trailer while it is moving, the coupler is doing work.

. . . . . Oh . . . I've seen the light!! . . . ergo . . . . my electric fan does no work while its running (at constant velocity) . . only when it accelerates when initially switched-on - COOL!

No. Your electric fan converts electricity into motion of the fan blades. To run at constant speed, it must constantly do work against the force of air resistance on the blades.

 

[wlminex]

. . .so . . . magnet=static field and gravity=static field . . . . and static fields do no work . . . why then do we refer to the 'acceleration' due to the gravitational field as what holds us to the earth's surface and not the 'acceleration' due to the magnetic field that holds a ball bearing onto a magnet? Guess it's just a question of semantics or of standard convention.

ps/Gibberish to some is considered thinking by others!

wlminex

 

[arfa brane]

Something can only be static in relation to something else.
A fixed magnet has a "static" field which is why fridge magnets stay put. The earth has a fixed gravitational field--you and any other object accelerate towards the centre of the earth, but the "fixed" surface stops your spatial acceleration.

Work only happens when energy is exchanged between the magnet and the fridge--if you remove a fridge magnet, you exchange energy with the field. Likewise if you move in a gravitational field, you are doing work by exchanging energy with the field.

Because of this "exchange principle" you can't get useful work for nothing. Even a superconductor that has no resistance needs a lot of energy input to have a "perpetual" current flow.

Capische?

 

[wlminex]

JamesR Post #9"

so . . . if my fan is running in a vacuum, with no friction due to air resistance, it is not doing any work? . . (albeit, not much purpose in a fan running in a vacuum!) . . . But suppose the blades were replaced with a disk containing radial slits to 'chop' an incident laser beam. Since the laser beam has no real mass (only massless photons = energy), the rotating slits would also be doing no work in chopping the laser beam.

More gibberish, I suppose . . . . sorry I capische english by preference

wlminex

 

[Read-Only]

Something can only be static in relation to something else.
A fixed magnet has a "static" field which is why fridge magnets stay put. The earth has a fixed gravitational field--you and any other object accelerate towards the centre of the earth, but the "fixed" surface stops your spatial acceleration.

Work only happens when energy is exchanged between the magnet and the fridge--if you remove a fridge magnet, you exchange energy with the field. Likewise if you move in a gravitational field, you are doing work by exchanging energy with the field.

Capische?

Energy "exchanged"???? I hardly think so!!

In truth, it's just a very simple matter of energy being expended when motion is created in resistance to the fields you mentioned. And that energy is dissipated in the form of heat. Period.

 

[James R]

. . .so . . . magnet=static field and gravity=static field . . . . and static fields do no work .

No. For example, the "static" gravitational field of the Earth does work every time you drop something. Potential energy in the field is converted into kinetic energy as the field does work.

. . why then do we refer to the 'acceleration' due to the gravitational field as what holds us to the earth's surface and not the 'acceleration' due to the magnetic field that holds a ball bearing onto a magnet? Guess it's just a question of semantics or of standard convention.

If you're standing still on the Earth's surface then there's a gravitational force on you, but that force is doing no work since you aren't moving. You're not accelerating either.

ps/Gibberish to some is considered thinking by others!

Bear in mind that sometimes you're actually talking to people who have actually studied science at university level on this site. Your gibberish won't fly with us. It might convince your workmate at McDonalds.

so . . . if my fan is running in a vacuum, with no friction due to air resistance, it is not doing any work? .

There's probably still some friction in the bearings etc., but that will be small compared to the usual air resistance. So, essentially it won't be doing any work.

(albeit, not much purpose in a fan running in a vacuum!) . . . But suppose the blades were replaced with a disk containing radial slits to 'chop' an incident laser beam. Since the laser beam has no real mass (only massless photons = energy), the rotating slits would also be doing no work in chopping the laser beam.

Photons carry momentum, so photons hitting the blades would exert a tiny force on the fan. The work required to keep the fan spinning would be minuscule.

 

[wlminex]

arfa brane Post#7:

. . . so a magnet suspending a steel ball against gravitational acceleration is different than the earth's surface holding one's body against gravitational acceleration. Looking for consistency here. By the way the gibberish is working . . . you guys are at least thinking!!

Regards,

wlminex

 

[James R]

. . . so a magnet suspending a steel ball against gravitational acceleration is different than the earth's surface holding one's body against gravitational acceleration.

Not much.

In both cases there's a force of attraction. In both cases there is a contact force that fights the attraction. In both cases the net result is zero motion. In both cases the attractive forces do no work.

By the way the gibberish is working . . . you guys are at least thinking!!

On a scale of 0 to 10 of my thinking power, this is taking up about 0.5.

 

[arfa brane]

Energy "exchanged"???? I hardly think so!

But when you do work pulling magnets apart, you do exchange one form of energy for another. You exchange work for magnetic energy when you pull a fridge magnet away from the metal door.

The energy may dissipate, but that's because your body doesn't store it.

 

[wlminex]

JamesR:

"On a scale of 0 to 10 of my thinking power, this is taking up about 0.5."

That's about how much I would estimate also!

"a contact force that fights the attraction"? Fighting sounds like hard "work"!

Oh well . . . my shift at McDonalds is about over . . . . thanks for your input guys. All 'youse other research scientists' keep in mind two cornerstones of the Universe - levity and brevity.

wlminex

 

[wlminex]

"Thinking is a good exercise against alzheimers!"

 

[Read-Only]

But when you do work pulling magnets apart, you do exchange one form of energy for another. You exchange work for magnetic energy when you pull a fridge magnet away from the metal door.

The energy may dissipate, but that's because your body doesn't store it.

Your first statement (above - the second sentence) is pure nonsense. :bugeye:

I assume you attended a reputable school, correct? Then whoever paid for it should sue for damages because you completely failed to learn even the very basics of physics.