Exploring the Possibility of Highly Efficient Energy-to-Mass Converters

[chingel]

I too have the question how does the energy disappear when it is being moved up using gears.

Do the gears resist somehow? If we take two scenarios, in one the force is transferred toward the ground and in the other it is transferred up, does it get a boost in one case and feels a drag in the other case? If I have a spinning wheel, does the gravity somehow affect it differently the wheel depending on whether I connect something to it on the bottom or the top?

Since energy has mass, how does gravity affect the transfer of energy through a rotating gear? How does it work?

 

[guss]

Ok, I have managed to distill our argument into another awesome diagram.

Does anyone have an answer?

 

[I like Serena]

Does anyone have an answer?

Still conjecture, but I'm thinking General Relativity.

The gravity field would have a gradient, effectively resulting in changing time dilation.
I suppose that the change in electric/electromagnetic field is for the same reason.

 

[Antiphon]

The mass at the top is higher than it is at the bottom so there's more energy at the top.

Once the paddle wheel is turned, that additional energy which would have become kinetic in free-fall is lost to the paddle wheel.

The particles at the bottom, even when turned into energy need to be lifted against gravity.

You cannot lift energy or matter against gravity without an additional energy source. This source is not in the diagram.

 

[guss]

The mass at the top is higher than it is at the bottom so there's more energy at the top.

Once the paddle wheel is turned, that additional energy which would have become kinetic in free-fall is lost to the paddle wheel.

The particles at the bottom, even when turned into energy need to be lifted against gravity.

You cannot lift energy or matter against gravity without an additional energy source. This source is not in the diagram.

But why can't I just run a motor with that energy from the matter, then have gears leading to the top where there is a generator (all 100% efficient)? Where does the energy go?

 

[willem2]

I think an observer at the bottom of the toothed wheel will see it move faster, due to time dilation, so he must put in more energy to push the wheel with the same force as someone at the top of the wheel.
If the frequency of the photons coming from above goes up, so must the number of teeth/second that goes by.
You might better ask this on the relativity folder however.

 

[chingel]

Does potential energy have mass too?

When the weight is at the top, it has potential energy which gets converted into kinetic energy. It gives the kinetic energy to the wheel and at the bottom it has neither the kinetic energy nor the potential energy anymore, so it must have less mass. Is this a right way of thinking?

This would mean that the object at the bottom has less mass and if you transfer it up, you wouldn't lose any energy during the transfer, because as it is being hauled up, it gains potential energy which increases mass by as much as it takes energy to haul it up. Is this true?

 

[guss]

This would mean that the object at the bottom has less mass and if you transfer it up, you wouldn't lose any energy during the transfer, because as it is being hauled up, it gains potential energy which increases mass by as much as it takes energy to haul it up. Is this true?

Not true. The potential energy does not increase the mass.

 

[Vanadium 50]

General relativity? Good heavens!

This is a simple problem. What is the energy required to lift a mass m a distance h in a gravitational field g? You can try and Rube Goldberg it up with wires and gears and magical energy-to-matter converters, but the answer is the same: mgh, no matter how many intermediate complications you add.

 

[guss]

General relativity? Good heavens!

This is a simple problem. What is the energy required to lift a mass m a distance h in a gravitational field g? You can try and Rube Goldberg it up with wires and gears and magical energy-to-matter converters, but the answer is the same: mgh, no matter how many intermediate complications you add.

What mass are we lifting here?

 

[Antiphon]

Yes, the potential energy increases the mass.

We had to invoke GR. This is because electricity flowing up from the ground to an upper floor doesn't suffer a potential energy decrease as mgh. Only in GR do you have this effect.

 

[brocks]

This is kind of similar to those troll science threads, but what am I missing here?

What if those energy-to-mass and mass-to-energy converters can reach 99.999% efficiency when converting to electricity to mass and vice versa in the future? Those converters are theoretically possible, aren't they?

Don't know, but assume they are. Then you already have a device (your mass-energy converter) that let's you throw dirt into it and get gigawatts out of it. So why would you plug it into the contraption in the picture?

 

[danR]

What mass are we lifting here?

I'm wondering too. Nope, I don't see it. Maybe we're lifting a strawman.

 

[Vanadium 50]

Mass enters the bottom trapezoid and reemerges from the top. That's "lifting", no matter how you slice it.

 

[danR]

This is getting confusing because people are now answering to 2 different diagrams.

 

[bcrowell]

Ugh, what a mess. This thread started off with an example that basically had nothing to do with relativity. Then guss made a new (interesting!) version that did have to do with relativity, but posted it both here and in the relativity forum. Guss, please don't duplicate threads like that -- it's inconsiderate, because people expend double the effort and it wastes their time. Discussion has been going on for quite a while now in both threads, so it's not practical to combine them. Since this thread has been mostly about example #1, and the other thread has been mostly about example #2, I'm going to close this thread and ask that anyone who has been participating in this thread's discussion of #2 do so in the thread in the relativity forum.