It's a system. Why do you want to take one piece of the system away and try to equate the results to results with all the parts to the system in place? That's like taking the number 5 out of the number line and saying that 10 is actually 9 without the number 5.
Helium is not mined from the upper atmosphere, but mostly extracted from oil wells and natural gas deposits, because the same impermeable rocks that trap these deposits often act as a barrier to helium. As a product of radioactive decay (alpha particle = helium nucleus), helium seeps upwards from permable strata with heavy radioactive elements. http://en.wikipedia.org/wiki/Helium#Modern_extraction Your "Natural State" hypothesis makes no sense in combination with the observation that all known gold mines are found within a few km of the surface. Your "there is no backwards" claim makes you a stranger and outsider to physics discussion since at least 1638 and Galileo's last publication.
So a force is holding the helium down, and when the force is released it travels away from the core? That's what I just said. If the force is released the helium moves away, towards its proper density area. ...and can you prove the backwards motion? relative to the road?
Ok to the ones that actually understood the question and answered, thank you. To the others, I am asking why the balloon would move forward, not upward. I know why balloons float lol
In a way, the answer is the same for both. Let's put it his way: if you black out the windows of the car, there is no way for anything in the car to tell the difference between the car accelerating on a level surface and it traveling up an incline at a constant speed. Everything in the car will behave the same way in both cases with respect to the car.
Why do balloons float? Because they're lighter than air? But how does that make a balloon float? If you really think through why a helium balloon floats, then it will be easy to see why it moves forward in an accelerating car.
If it is traveling away from the center of the Earth the force is getting less, whereas a constant acceleration on a road curved with the Earth (equal distance away from center of Earth at all times) doesn't get less.
Because the balloons contents are lighter than the surrounding air and that makes it easier to move in the direction of the acceleration which, in most cases, is more desirable.
The laws of nature apply to humans and balloons, concrete, ants, cities, galaxies etc. and absolutely everything the same. So I'm not sure why bring this up. It is unnecessary information as everything is part of nature. While humans and wood float in water, a helium balloon would float out of water. Again, I'm not sure why you bring this up.
Not the same though. Just showing how the substance surrounding an object makes a difference. Could be air or it could be water and that is the premise behind air (actually wind) effecting the direction of the balloon in an enclosed vehicle. The op implies it is wind even though the term air is used because it suggests the movement is due to the air moving. The thing is the object needs to have a certain mass to it to be effected because of you hold up a small strip of paper then the paper remains unaffected. However, in wind the paper would be the most obviously affected by the wind. My conclusion is inertia causing what transpires in op. This is not nitpicking because here is the OP claim: Answer: The balloon goes forward. The reason it floats is because the air in the car pushes it upward. Now if the balloon was held by a string would it not react the same way? So why would it moving up make a difference in the forward or backward movement?
Irrelevant to the discussion. The constant speed on the Incline could be zero. (relative to the Earth)
Then why did you bring it up? You said: How could the speed be zero, and "it traveling up an incline at a constant speed" at the same time?
This smells a lot like bovine excreta. Why do you suggest that moving in the direction of the acceleration is "more desirable"?
Some serious confusion here. John99: How do you breathe in a sealed car? Hint: maybe there's some air in there. Yes. What determines whether an object floats upwards or downwards depends on relative density. Wood floats on water because it is less dense than water. Wood does not float upwards in air because it is more dense than air. A helium balloon is less dense than air. Did you understand my post where I explained the answer in terms of buoyancy (which is not due to gusts of air, by the way). Inertia of what? How? Explain. Motor Daddy: Gravity is a force that is always attractive - it always pulls things down towards the centre of the Earth, including helium. Your idea of a repulsive gravitational force that pushes helium up from the core of the Earth is deeply misguided. I don't know where you would get such an idea. This is a matter of your particular frame of reference, and is probably too complex a matter to go into here. We don't need to consider it to answer the question, anyway.
Pulls things down relative to the Earth? I've never seen a helium balloon fall to the ground when released, have you? If I hold a helium balloon 10 feet above the ground and then release it, how much time does it take to hit the ground? Does it accelerate towards the center of the Earth at the rate of 32.174 ft/sec^2? If not, at what rate does it increase velocity towards the core? My idea is what happens. Measure it yourself. Take a helium balloon and release it and you will notice that the balloon will accelerate away from the center of the Earth, and that you can measure the distance and time traveled away from the center of the Earth. Do you doubt that? Where do you get the idea it gets closer to the core? Also, I didn't say it was pushed up or that gravity was repulsive. To the contrary, I said you had to force the helium balloon to the surface, away from its natural outer position in the Earth's density order. In what frame does the human travel backwards?
Motor Daddy: That's because you've never pumped all the air out the room you're using the helium balloon in. Gravity is not the only thing acting on the helium balloon. If it was, the helium balloon would indeed drop to the ground. The force you're ignoring is the one I've already explained - the buoyant force of the air pushing the helium balloon upwards. That's not repulsive gravity. If you do it without any air around, the helium balloon will indeed accelerate towards the centre of the Earth at 32.174 ft/sec^2. Do you disagree? What do you think the force is that you're fighting, when you move the balloon from it's "natural" position? You say it's not repulsive gravity, so what do you think it is? To put the question another way: what kind of force do you think "restores" a helium balloon to its "natural" place in the "density order", if you move it away from its natural place? In any frame travelling faster than the human. Why do you ask?
