Phantom flying and the theory of relativity

Actually, it likely hit me AFTER the end of deceleration when momentum of the ribbons caught up.

I'm not sure... I'm still recovering from the concussion.
 
When you decelerate a vehicle, everything in it moves or tries to move forward. An object in motion stays in motion until a force is applied to it.
Even the air in the vehicle moves forward somewhat. When I make turns, I can feel changes in air temperature due to the uneven AC cooling in my car.
 
When you decelerate a vehicle, everything in it moves or tries to move forward. An object in motion stays in motion until a force is applied to it.
Even the air in the vehicle moves forward somewhat. When I make turns, I can feel changes in air temperature due to the uneven AC cooling in my car.

That's a correct observation, but an incomplete analysis of the dynamic forces on the objects in the vehicle. To illustrate the subtlety, consider the statement that gravity makes all objects move, or try to move, downwards. Except that buoyant objects, such as helium balloons, do not - they move upwards, due to Archimedes Principle. Extending that, since acceleration/deceleration is indistinguishable from gravity, and since buoyant objects experience a net force in the direction of the acceleration vector, rather than against it, then in a decelerating vehicle a helium balloon will tend to move upwards (as usual) and backwards (rather than forwards). Very simple to test, even if you doubt the physics.
 
Was it some sort of time dilation that brought this thread back after 9 months?
 
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Likely the balloons would be already on the ceiling or restrained by a tether as high as it can go. Therefore all that's left is horizontal motion, with some decent in the case of a tether. On completion of deceleration and balloon has gone as far forward as it can go, then it would move back as it goes back up on its tether. But it's initial move has to be forward.
 
Likely the balloons would be already on the ceiling or restrained by a tether as high as it can go. Therefore all that's left is horizontal motion, with some decent in the case of a tether. On completion of deceleration and balloon has gone as far forward as it can go, then it would move back as it goes back up on its tether. But it's initial move has to be forward.

No - that's not correct. This has nothing to do with tethers. What part of my explanation of the physics did you disagree with?
 
Probably the part about the balloon going up when it is already as up as it can go before and during deceleration.
 
Probably the part about the balloon going up when it is already as up as it can go before and during deceleration.

I have no idea what you mean by that. Let me just point out that this is a classic contemporary physics question and the answer is not in any way in doubt. If you were not convinced by my explanation then you can find many articles on the subject. For example, from Scientific American:

Buoyant Balloon: Float Forward with Fluid Physics
 
OK, I found a key to the puzzle on Wired. The issue is the air in the vehicle outside of the balloon. I was right when I mentioned earlier that the air in the vehicle moves forward when you decelerate so it is more dense in the front of the vehicle than the rear, so the balloon effectively slides down the air density thus moving backwards.
Might be easier to visualize with water and a ball. Water sloshes forward making a wave sloping up from back to front. Ball falls down the wave, effectively moving the ball back.
Didn't think the air density change would be enough to counter the balloon inertia, but then the balloon has insufficient mass for its inertia to go up the "hill of air"
 
Have another beer and give it a go, unless
You already have,i only
Read the first post.
 
Your phantom would first simply appear to hover, but if the RV is made of metal, the phantom child would give you a compass error then bolt off at a tangent path to the closest toilet bowl.
 

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