Perpetual motion?

[Guy Fawkes]

As I said above, it doesn't create the potential energy. If there's a weight on the floor, how does that weight get potential energy?

If that floor underneath it were to suddenly vanish, and nothing else were to exert any force onto that object, what would happen to it?

Would it stay put? or would it drop until it hit something to stop it falling further? - If it drops, then it surely has potential energy
(the energy for this is already stored there in getting it to that height from the centre of the planet where the gravitational pull is greatest and everything on the planet is trying to fall to)

Another example is if you throw a ball into the air what happens? does it keep rising or does gravity pull it back to the ground? Your energy input was to raise it to a greater height so how does it fall again if the force of gravity isn't overcoming this and making it drop again (or is that all down to air resistance, both up and down that makes it drop?)

 

[Guy Fawkes]

No, the other way around. When it was up higher, it had more potential energy.
They have less potential energy as a result of falling.

Yes.

And the Sun's energy will heat more air and water which will cause the air to contain more moisture, which will rise and form clouds, which will fill the reservoir.

The release of that potential energy has occurred due to gravity's effect on moving it from a greater height to a lower height (which is what i guess the previous poster was getting at when talking about the PE of the effect of gravity)

And also does that single molecule of water (H2O), if destroyed at different altitudes into single atoms, release different amounts of energy solely as a result of that molecules destruction?

 

[Jimmy Grimble]

What happens when an unstoppable force meets an immovable object?

 

[Triggaaar]

If that floor underneath it were to suddenly vanish, and nothing else were to exert any force onto that object, what would happen to it?

Well if the floor is earth, and the whole of earth vanished - not a lot. But let's just say it was upstairs, and upstairs vanished - then it would fall and release the potential energy it always had. Just as objects on the outside floor have potential energy, all you need to do to release it is to dig a hole.

Would it stay put? or would it drop until it hit something to stop it falling further? - If it drops, then it surely has potential energy

Yes, it has potential energy.

(the energy for this is already stored there in getting it to that height from the centre of the planet where the gravitational pull is greatest and everything on the planet is trying to fall to)

Sort of agreed, but it's not quite that simple. Mass that's close to the centre of earth is not actually feeling much gravitational putt at all, as it's got mass all around it pulling it in different directions, which cancel each other out. From where we stand, the whole mass of earth is pulling us in roughly the same direction.

Note that although a lot smaller than earth, and a long way away, the moon is still able to reduce the effect of earth's gravity on us, which is why we have tides.

Another example is if you throw a ball into the air what happens? does it keep rising or does gravity pull it back to the ground? Your energy input was to raise it to a greater height so how does it fall again if the force of gravity isn't overcoming this and making it drop again (or is that all down to air resistance, both up and down that makes it drop?)

When you throw it, you give it kinetic energy. Because of gravity, that kinetic energy is converted to potential energy the higher it gets. When it starts falling, that potential energy starts converting back to kinetic energy. Some energy is converted to heat and sound due to friction. All the energy is then converted to heat and sound when it lands.

 

[Guy Fawkes]

Whatever energy the machine started with, is lost as the ball makes noise and heat, and as the springs etc make heat. It's that simple.

I've got a 100 year old wind up clock that you can watch run for 8 days without slowing down if you want.

To if you had another wind up watch that only lasted for 2 days, they will be considered as efficient as each other?

The video says it's much more efficient that other engines (mainly because we extract energy from that engine to power other things but this machine doesn't lose energy in powering other things) and therefore closer to 100% that other engines / machines (but not 100%)

Presumably those magnets are powered by electricity, so it's not a scaled down version.

Hence why i said similar principle. So if that train had magnets that were not electromagnets, but ordinary magnets and the magnet was moved away as the train approached in some way so that the other magnets further up the line were attracting the train, overcoming the effects of the one(s) that it was traveling over.

This machine dips the relevant magnet out of the way as it approached using pendulums which are also powered by magnets, allowing those further ahead of the ball to pull it towards itself and by using momentum from the dipping track way, again thanks to the pendulum and magnets. This pendulum aspect is probably the part which will likely run out of energy first, causing the machine to fail.

It is not potential energy, it's an interesting concept and seemingly fairly efficient machine

 

[Triggaaar]

The release of that potential energy has occurred due to gravity's effect on moving it from a greater height to a lower height

Yes, it wouldn't even have had that potential energy if it weren't for gravity.

which is what i guess the previous poster was getting at when talking about the PE of the effect of gravity

The point of the machine losing energy because of sound was raised, and gravity and magnetism being energy were given as a possible reason as to why energy was not lost. That wasn't correct.

Just because gravity is required for objects to have gravitational potential energy, does not mean that gravity itself is energy, nor that it can provide extra energy. If that machine makes noise, that energy is gone, and gravity can't help. All gravity can do is release more of the potential energy that was already stored (or convert some kinetic energy into potential energy, with a bit of a loss).

And also does that single molecule of water (H2O), if destroyed at different altitudes into single atoms, release different amounts of energy solely as a result of that molecules destruction?

Eh? If you convert split a molecule into its atoms, you don't lose energy as far as I know. They all still have the same potential energy.

 

[Guy Fawkes]

Well if the floor is earth, and the whole of earth vanished - not a lot. But let's just say it was upstairs, and upstairs vanished - then it would fall and release the potential energy it always had. Just as objects on the outside floor have potential energy, all you need to do to release it is to dig a hole.

Yes, it has potential energy.
*Sort of agreed, but it's not quite that simple. Mass that's close to the centre of earth is not actually feeling much gravitational putt at all, as it's got mass all around it pulling it in different directions, which cancel each other out. From where we stand, the whole mass of earth is pulling us in roughly the same direction.

Note that although a lot smaller than earth, and a long way away, the moon is still able to reduce the effect of earth's gravity on us, which is why we have tides.

When you throw it, you give it kinetic energy. Because of gravity, that kinetic energy is converted to potential energy the higher it gets. When it starts falling, that potential energy starts converting back to kinetic energy. Some energy is converted to heat and sound due to friction. All the energy is then converted to heat and sound when it lands.

Take out the throw into the air and that PE exists, as you say it is converted into another form of energy if it were to drop to a lower height again (the potential energy which can be released as kinetic energy when gravity effects an object and makes it fall towards a lower point ergo gravity has a PE effect on something without creating or destroying energy and breaking the thermodynamic law

(*Phrasing was wrong about the centre of the Earth in a previous post, it should have just been towards and not to reach the literal centre of the planet for the reasons you give, i was trying to keep it relatively simple in my example)

 

[Triggaaar]

To if you had another wind up watch that only lasted for 2 days, they will be considered as efficient as each other?

That depends. Depends how much energy you put into the spring.

The video says it's much more efficient that other engines (mainly because we extract energy from that engine to power other things but this machine doesn't lose energy in powering other things) and therefore closer to 100% that other engines / machines (but not 100%)

It's just a ****ing ball spinning round, it's not powering anything else. Let's get it to power something and see how efficient it is.

Hence why i said similar principle. So if that train had magnets that were not electromagnets, but ordinary magnets and the magnet was moved away as the train approached in some way so that the other magnets further up the line were attracting the train, overcoming the effects of the one(s) that it was traveling over.

Meh. Trains are a bit heavier that that ball, and it's not so easy to keep lifting the ground so that the trains run downhill. It's also harder to give the train the big push. The the wind resistance when the train is moving at speed is quite a lot more that on that poxy ball.

It is not potential energy

There are only two basic types of energy - kinetic and potential. The bits that are moving have kinetic energy, and the spring that are wound have potential, the pendulums at the end of their stroke have potential, etc.

I've now watched a few more seconds - the university guy says he's amazed by the ingenuity of it. Cool. He says it's maybe 80 or 90% efficient. Great, well done. If the video was 'look at this cool machine, it's really efficient', there'd be no problem.

 

[Triggaaar]

Take out the throw into the air and that PE exists, as you say it is converted into another form of energy if it were to drop to a lower height again (the potential energy which can be released as kinetic energy when gravity effects an object and makes it fall towards a lower point ergo gravity has a PE effect on something without creating or destroying energy and breaking the thermodynamic law

If you're saying that you can drop an object, and gravity will convert its potential energy into kinetic energy, then yes, that's right. What's your point? My point is that gravity is not adding any energy, just as gravity can't add energy to that machine.

 

[Easy 10]

I bet there's not another football forum on the planet that has a 5 page thread like this.


Goodnight.

 

[Guy Fawkes]

Yes, it wouldn't even have had that potential energy if it weren't for gravity.
The point of the machine losing energy because of sound was raised, and gravity and magnetism being energy were given as a possible reason as to why energy was not lost. That wasn't correct.

Just because gravity is required for objects to have gravitational potential energy, does not mean that gravity itself is energy, nor that it can provide extra energy. If that machine makes noise, that energy is gone, and gravity can't help. All gravity can do is release more of the potential energy that was already stored (or convert some kinetic energy into potential energy, with a bit of a loss).

Eh? If you convert split a molecule into its atoms, you don't lose energy as far as I know. They all still have the same potential energy.

So that difference in energy has to come from somewhere when power is generated by water moving from a reservoir above a dam to a lower level after passing through and powering turbines. The water molecule itself doesn't change into a different molecule so no endo- or exo-thermic reactions providing energy (The only sources are the release of kinetic energy from the effect of gravity pulling that water to a lower level, the destruction of some water molecules whilst going through the turbines leading to the thermic reaction or a mixture of both?) the turbines are moved by the force of water hitting rotor blades forcing them to rotate and turn, leading to the generation of electricity, as it is sealed, it's unlikely that water is lost so it is either smashed into Hydrogen and Oxygen or remains and the gravitational effect is used instead

(this has been about earlier posts saying that gravity can't lead to potential energy which these examples were about showing that gravity can)

 

[Guy Fawkes]

If you're saying that you can drop an object, and gravity will convert its potential energy into kinetic energy, then yes, that's right. What's your point? My point is that gravity is not adding any energy, just as gravity can't add energy to that machine.

But gravity is being used to convert potential energy into kinetic energy in that machine by the dropping of the track to make it so that the track just in front of the ball is the lowest point, helping the ball move around (also aided by pendulums and magnets to keep it moving)

 

[Triggaaar]

So that difference in energy has to come from somewhere when power is generated by water moving from a reservoir above a dam to a lower level after passing through and powering turbines.

Yes, the water started with lots of potential energy, and it finished with less. That's the difference. From that difference we get power in the form of electricity.

(this has been about earlier posts saying that gravity can't lead to potential energy which these examples were about showing that gravity can)

The gravity has just helped change the potential energy of the high water into electricity. Gravity hasn't added energy.

 

[happypig]

One thing I'd like to know, is where they found people stupid enough to watch that for 3 days?

http://www.northstandchat.com/showt...Preston-Park&p=7699533&viewfull=1#post7699533

 

[Triggaaar]

But gravity is being used to convert potential energy into kinetic energy in that machine by the dropping of the track to make it so that the track just in front of the ball is the lowest point, helping the ball move around (also aided by pendulums and magnets to keep it moving)

Smoke and mirrors. It's a cool little machine, but don't be fooled by its intricacies. So what if gravity is converting potential energy too and from kinetic energy? That's exactly what happens in Newton's cradle (that desk toy where balls swing back and forth).

 

[Triggaaar]

http://www.northstandchat.com/showt...Preston-Park&p=7699533&viewfull=1#post7699533

 

[beorhthelm]

It is not potential energy, it's an interesting concept and seemingly fairly efficient machine

toy. its an efficient toy. it doesnt do any work.

 

[Brovion]

I posted something that looks interesting and people want an argument over it

Well you did say 'Perpetual Motion' and then added a question mark, thus inviting a debate.

Of course there is no debate. It's not a perpetual motion machine. A perpetual motion machine is a closed system and at the very least nothing is making up the friction energy lost by the ball as it travels around the track.

 

[Brovion]

Is it a lump of coal or a man made weight? Perhaps a rock,that has solar energy in it......

No it doesn't have any energy any more than a bit of wood does or a two-pound bag of sugar. It can of course be converted into energy but that isn't the same thing.

 

[Triggaaar]

Is it a lump of coal or a man made weight? Perhaps a rock,that has solar energy in it......

No it doesn't have any energy any more than a bit of wood does or a two-pound bag of sugar. It can of course be converted into energy but that isn't the same thing.

To be fair, he was probably just taking the piss, as of course it posses potential energy (like chemical and nuclear). But he knew what I meant