# Can Centripetal Force create Gravity?

by oragami
Tags: centripetal, force, gravity
 P: 5 What i'm trying to get at is this, can a spinning framework of rings build enough centripetal force to keep a mass of liquid at the centre of the frame work? And if so what would be the relationship and conditions that would have to be met? Really need help:|
 Sci Advisor P: 5,776 A spinning fluid would tend to go the outside, not toward the center. That is the principal of the centrifuge.
 P: 5 well thank you mathman
P: 5

## Can Centripetal Force create Gravity?

but i ment if the sphere was spinning and like a gas was in it, if most of the gas would travel towards the centre. Please advice
 P: 102 Is that the whole notion behind artificial gravity in a spacecraft? A spinning spacecraft can reproduce the effects of gravity if I am not mistaken?
Mentor
P: 14,665
 Quote by oragami but i ment if the sphere was spinning and like a gas was in it, if most of the gas would travel towards the centre. Please advice
The gas will not go to the center. Why do you think it would?
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 Quote by oragami but i ment if the sphere was spinning and like a gas was in it, if most of the gas would travel towards the centre. Please advice
NO, it wouldn't. It would travel toward the circumference. That was mathman's point.
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 Quote by math_04 Is that the whole notion behind artificial gravity in a spacecraft? A spinning spacecraft can reproduce the effects of gravity if I am not mistaken?
People walking on the inside wall of the spinning space craft (heads pointed toward the axis of rotation) would feel a force pushing them against the space craft. Than can "simulate" gravity but will not be exactly the same. For example, in all but an immense space craft, coriolis forces would be evident.
 PF Patron Sci Advisor P: 8,896 A spinning fluid mass would resemble a galaxy in deep space. Gravity limits the effects of centripetal force.
P: 1,250
 Quote by Chronos A spinning fluid mass would resemble a galaxy in deep space. Gravity limits the effects of centripetal force.
I have no idea what you are trying to say? In a galaxy gravity is what provides the centripedal force that keeps it together??
P: 5,776
 Quote by Wallace I have no idea what you are trying to say? In a galaxy gravity is what provides the centripedal force that keeps it together??
In a galaxy the centripetal force is gravity.
 Sci Advisor P: 1,250 Yes, that's what I said? At least that was what I intended to say....
P: 12
 Quote by oragami What i'm trying to get at is this, can a spinning framework of rings build enough centripetal force to keep a mass of liquid at the centre of the frame work? And if so what would be the relationship and conditions that would have to be met? Really need help:|
Yes...Theoreticaly this is possible. For simplisity sake take for example a ring and contain within it two elements... one a gas and other liquid. Let the gas be significantly "heavier" than the fluid. When spinning centripetal force would pull the heavy gas to the outside and leave the fluid (lightier) in the center...Is this even what you are asking???
 P: 12 However, I don't know of any Gas heavier than liquid... so in accuality I dont think so
 P: 61 So is the difference in behavior mainly due to the atomic freedom that exists in gasses Does this amount to saying that randomly circulating gas molecules cannot be bound by the centripetal force? How does gravity keep them together, is gravity stronger than centripetal force?
P: 12
 Quote by raknath Does this amount to saying that randomly circulating gas molecules cannot be ?bound? by the centripetal force? How does gravity keep ?them? together, is gravity stronger than centripetal force?
Can you please explain in more depth what you are saying? What centripetal force are you refering to??
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 Quote by raknath So is the difference in behavior mainly due to the atomic freedom that exists in gasses Does this amount to saying that randomly circulating gas molecules cannot be bound by the centripetal force? How does gravity keep them together, is gravity stronger than centripetal force?
Several levels of issues here:

1) One is called 'miscibility' see: http://en.wikipedia.org/wiki/Miscibility

2) Whether 'randomly circulating gas molecules' are 'bound' depends on their energy and strength of the forces involved.

3) In this particular case, the substances appear to be already contained -- according to the original question. So this should not be an issue.

4) Actually, in the case as presented -- a gas -- the presence of gravity or centripetal or any force is really unimportant. The gas is going to fill the volume.

5) A liquid would only maintain being a liquid in the presence of additional gas (of some kind) filling any extra volume (or vaporize to expand to fill the volume)

6) If the containing object (spaceship) is spinning, the denser material will settle against the outer 'walls'.
 P: 61 Consider a box with some gas and a lot of holes(very hypothetically) Let us say i send the box into revolutions, now by what we have seen the gas would escape out of the holes, as the box rotates? Now however if the gas is gravitationally bound like it is for say jupiter, the gas does not escape, i mean why is this any different? Does this mean that gravity influences gas molecules differently than it is affected by centripetal force?

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