Too good to be true?

[Xenophon]

Except on CUK.

Anything is possible on CUK.

[Spacecadet]

Anything is possible on CUK.

Threaded

[TimberWolf]

Secondly voyager has travelled from point A (earth) and is going to point B (whatever it crashes into or starts orbiting), from my recollection large amounts of rocket propellant were needed to get it going on its merry way.

Yes, fuel was used to reach escape velocity. Different potential. In flat space an infinitesimally small nudge would cause it to move and it would continue to move indefinitely for an indefinite distance in any direction you like. In principle - ignoring anything it encounters on the way.

For me to get into a vehicle and travel from point A to a point B to get off again, no matter where those points are, unless there is a potential difference in energy to be taken advantage off (e.g. going downhill) then there will have to be energy expenditure.

Didn't you read the link about the gravity train? With this you can travel anywhere on Earth in 42 minutes for no energy expenditure - in principle. In practise, as I say, there will be losses, perhaps even big ones, but the laws of physics don't state what these losses need be, even if A & B are separated by a large distance. It doesn't say for example that it must cost you X joules of energy to get from Swindon to London. The key thing is, as I said at the start is, in principle it takes no energy to go from point A to B. In practise, especially when using a car, work is being done on the environment but these losses can be minimised, perhaps arbitrarily close to zero.

So to get the fluid moving you need energy, glad you agree with that.
And to keep it moving with no potential difference between start and finish requires a super fluid and in this case will also need a tube which is cold enough to allow the super fluid to remain a super fluid. Its not called a super fluid for nothing

It's one of a number of examples I gave of the principle of no work being done to move from A to B. You aim to get as close to that as possible in practise.

[TimberWolf]

You canna change the laws of physics Captain.

Except on CUK.

You canna state simple physics laws on CUK. It's Copernicus all the way

[Spacecadet]

Yes, fuel was used to reach escape velocity. Different potential. In flat space an infinitesimally small nudge would cause it to move and it would continue to move indefinitely for an indefinite distance in any direction you like. In principle - ignoring anything it encounters on the way.

Nudge to start, nudge to stop. Both require energy... QED I win

Didn't you read the link about the gravity train? With this you can travel anywhere on Earth in 42 minutes for no energy expenditure - in principle. In practise, as I say, there will be losses, perhaps even big ones, but the laws of physics don't state what these losses need be, even if A & B are separated by a large distance. It doesn't say for example that it must cost you X joules of energy to get from Swindon to London. The key thing is, as I said at the start is, in principle it takes no energy to go from point A to B. In practise, especially when using a car, work is being done on the environment but these losses can be minimised, perhaps arbitrarily close to zero.

I don't think you read it... i'm not even going to bother with this you're so far off the mark.
To put it simply, to acheive the perfect conditions of no frictional losses is either impossible to attain, or require energy to acheive, i.e. maintaining a perfect vacuum.

It's one of a number of examples I gave of the principle of no work being done to move from A to B. You aim to get as close to that as possible in practise.

close but impossible to acheive

In principle it always takes some energy to move and that amount of energy will always be measurable

[TimberWolf]

Nudge to start, nudge to stop. Both require energy... QED I win

It was an example where an infinitesimal small energy input, arbitrarily close to zero, allows an infinite distance to be travelled for an infinite period passing through an infinite number of points in-between.

o put it simply, to acheive the perfect conditions of no frictional losses is either impossible to attain, or require energy to acheive, i.e. maintaining a perfect vacuum.

Yes, in practise it is difficult to attain, I never stated otherwise. You try to minimise losses and that minimum is zero.

In principle it always takes some energy to move and that amount of energy will always be measurable

Strictly speaking energy, like speed, is relative so the object could have any amount of kinetic energy. I think you mean it takes energy to accelerate, but again that's not true as you could see if you read that link I gave on the gravity train, or if you drop something.

[DimPrawn]

Strictly speaking energy, like speed, is relative so the object could have any amount of kinetic energy. I think you mean it takes energy to accelerate, but again that's not true as you could see if you read that link I gave on the gravity train, or if you drop something.

He's right. As long as your car journey is always downhill, you don't need any energy to get there, gravity does it all for free!

HTH

[TimberWolf]

Er, when you drop something it loses potential energy and gains kinetic energy.

Or at least it used to.

And the total mechanical energy at the start and end is?

We may be making progress here...

[TimberWolf]

He's right. As long as your car journey is always downhill, you don't need any energy to get there, gravity does it all for free!

HTH

See the link on the gravity train please FFS DP Everywhere is downhill.

[Advocate]

Er, when you drop something it loses potential energy and gains kinetic energy.

Or at least it used to.

What if I drop a helium filled balloon?

Or, as I hear is the word "on the street", what if I drop some phat[sic] beats?

I've also been known to "drop a right clanger" in the past.