Re: OT Here is an example of pseudo science.

[dennis]

Shame you don't read what I write, I have explained it before but it was ignored (not really a surprise, thin rick doesn't actually explain anything that is connected to the problem, he just invents something to deflect the issue and claims "its too hard for you to understand"..

but its all about energy *and* thrust, if one doesn't work the other can be ignored.

Say you have a cart travelling at 20 m/s with a wind behind it blowing at 10 m/s

The relative wind at the cart is 10 m/s to the rear.

Now to stop the wind behind you have to accelerate the air going past the cart to 20 m/s.

Now put E=mv2 into the picture and work out how much energy it takes to accelerate the air going past from 10 m/s to 20 m/s so it stops the wind from behind.

My simple maths tells me its 4 times the energy you get from stopping the wind .

Now if anyone can tell me how it stopping enough wind to generate four times the energy it releases I would be interested. I would like TNP to explain but he won't.

I would if the turbine was on the train and using the passing wind to generate the power or if the train was driven by a prop powered from the wheels. Other than that they have no relevance at all and its just another diverting tactic.

And while we are at it can anyone explain what the coupling is between the energy in the air that is stopped and the cart. Its all very well saying the energy is lost by the wind but there is no obvious coupling to the cart which is travelling faster than the wind.

I expect that it goes into turbulence and is just lost. Lets face it an airplane capable of doing 100 knots doesn't suddenly go > 10 knots faster flying downwind in a 10 knot wind so none of the energy released by stopping the wind is absorbed by the plane.

[Rick Cavallaro]

There's no need to stop the wind behind you. Just slowing it relative to the ground is sufficient. That means we only need to accelerate it (by any amount) relative to the cart.

I hope that's just a double typo.

[dennis]

OK so do it for 1 m/s then, you still lose energy from the cart, there is nowhere else for it to come from.

No it is not a typo, the energy of a moving object is mass x velocity squared. We can ignore the mass of the air unless you are creating a vacuum somewhere.

You are confusing it with E=mc2, not really surprising from someone who doesn't understand physics. I will give you a clue.. why does it take four times as long to stop a car from 20 mph as it does from 10 mph rather than twice as long. Please note that I said as long not as far, brakes approximately dissipate energy (into heat, they get hot as they are designed to do) at a constant rate.

[Doctor Drivel]

They machine to invent as an anti-gravity machine. That will give you perpetual motion. Have a weighted wheel. To one side of the wheel has no gravity the others side does. Weights take the wheel down. No gravity on the other side means the weight goes up and around and down again. The wheel turns forever.

A balloon is an anti-gravity machine, so is an aircraft. They defy gravity.

I saw a "perpetual motion" machine once. Weights pushed a wheel downwards. A balloon (anti-gravity machine) lifted the wheel up on the other side. A ratchet mechanism took the balloon from the top to the bottom of the wheel to lift again. It was largish and went on and on once started - pretty slowly. A large wheel I suppose with gearings could turn a generator.

[Clive George]

Ah, you're back. Would you care to reply to the post I made a couple of days ago?

Do you? Why is that?

I can also stop the wind with a wall, and I don't believe you'd claim that takes energy. So why do you need to invent that energy input?

Does a plane have a connection to the ground? I'm thinking generally speaking no, and when it does it's not via an arrangement such as is seen on those cars, merely a wheel possibly braked.

The connection to the ground is what makes this work, which is why thinking of planes is causing you to get it all wrong.

[dennis]

It does actually, it creates turbulence and ultimately warms the air from the energy taken from the wind..

The wall isn't moving faster than the wind is it? Why do you need to try and deflect the issue by bringing in a stationary wall. Why don't you try putting the wall on the back of a truck travelling faster than the wind and explain how that wall extracts energy from the wind? You can assume an infinite wall if you want.

Try again, you are the one wrong and the above energy statement proves it. Go and make a YouTube video with a moving wall that extracts energy from the tail wind, it should be easy for you as you appear to think a brick wall is the same as the propeller.

I am more surprised you didn't just say the formula was wrong as I omitted the constant because it didn't matter.

[Clive George]

No answer.

No answer.

Ok, no energy input from the wall.

Speaking of deflection, how about we stop this little sidetrack of yours and go back to where you still haven't answered my questions from a few days ago. Those questions aren't there to make you look stupid, they're intended to lead you to understand what's going on.

Your energy statement is bollocks.

No, the wall is pointing out why your energy argument is wrong.

Dennis, the thing works, we can see it works, we can do the physics to demonstrate why it works. You're starting from a position of "It can't possibly work", and distorting your knowledge of physics to try and fit that position. Instead of doing that, how about dropping that assumption, and do the physics properly? I've started to lead you through an explanation, but you refused to address it, complaining about "deflection". Go back to it and actually look at it, then reply here.

[dennis]

Cr@p posting.

Obvious to anyone with half a brain.

No answer, what a surprise? You brought in walls and now i have asked a more sensible question about moving walls you decide to try and deflect again.

there is a simple answer to all this, all you have to do is show where the energy is coming from. I have shown that you don't get it from the wind. the propeller is just a brake on the cart once you exceed the wind speed and probably before you do as its not 100% efficient.

You think my use of the conservation of energy is stupid, that makes you look more stupid.

Go on then explain where I am wrong. If you can't I think we can take it that the whole thing is just bull.

No the wall is irrelevant to my argument and is a attempt to deflect the argument.

You can't do the energy sums though can you? It easy enough..

relative speed of wind to cart speed of real wind accelerate the relative wind to be faster than the cart so it can actually slow the real wind. subtract the energies and prove you can get more energy from slowing the wind than from speeding up the wind.

Where have I distorted any physics? I don't need infinite props and stationary walls to distort things and trick people.

I have, you go on about thrust, but thrust is useless without energy. Show where you actually extract energy from the wind and get it onto the cart.

You can't.

You are wrong, there I have said what I think of your explanation. Prove the energy equation and I might believe you, until then you have no chance.

I also recommend you stop bringing in irrelevant arguments about static walls, carts on treadmills, etc. none of which answer the energy question, it makes you look like you are trying to avoid the truth.

[Rick Cavallaro]

Well there's your problem.

[Rick Cavallaro]

So it's not a double typo. It's a simple case of a double idiot. You got the formula wrong by a factor of 100% and you seem to think that simply sticking a "2" in there somehow automatically means "squared".

Sorry, my irony meter exploded on your previous post. I won't be able to process that sentence until the new one arrives.

It doesn't dumbass.

[Clive George]

Which bit of what I said is wrong? I hadn't even got as far as dealing with the wind.

I had my little car with a treadmill. Tell me what was wrong with the mechanics/physics of that.

[Roger Chapman]

You have been reading H G Wells.

No they are not. Balloons float and aircraft need some sort of motion to stay up. You might just as well call a boat an anti-gravity machine.

Your machine as described would not work. That is not to say that a series of devices that change size depending on their inclination couldn't rotate a wheel but it wouldn't go on for ever. They would be doing work and hence extracting energy from their surroundings. Put such a machine under water (the better to exploit the difference in buoyancy and the water would ultimately freeze if there wasn't an outside source to warm the water. I suppose that in modern parlance you could say entropy sucks.

[ThinAirDesigns]

harry >

A: wrong.

B: your own link says your wrong.

[dennis]

Sorry but you and rick are just too stupid to bother with.

[AL_n]

Roger Chapman wrote in news: [e-mail]:

PMFJI - Most people don't know that there are actually some gravity-powered devices in the world today. Many don't realise that this technology has actually been around for a while.

In 1782 the Montgolfier brothers built and manned such a device. It was a hot air balloon!

Al

[Clive George]

We've offered to help you understand, but you won't even try. Are you scared you might learn something?

[ThinAirDesigns]

dennis@home

Currently, the only "energy problem" here is the one where you incorrectly state that the the formula for energy is:

and

Just for your own education, here is the REAL equation for energy:

1/2*M*V^2 or ONE HALF mass x velocity squared.

[dennis]

You have repeatedly failed to answer the energy question and used diversionary tactics, are you scared others will learn something?

[Andy Burns]

Who says you have to STOP the wind? You just need to SLOW it to some extent, to do that you just have to accelerate SOME air past the cart.

[dennis]

I have news for you it doesn't. I also stated that I had ignored it because it didn't matter.

have you worked out why it takes four times as long to stop a car that is going twice as fast yet. You can use either formula to find out as the constant doesn't matter.