Having a problem with Centrifugal/Centripetal force in zero gravity

Crazymechanic

Maybe but you do feel the acceleration that gravity makes on you.While in the OP's original sense he speaks about a theoretical place with no gravity.In such a place you don't fall you don't feel anything but if you get in a rotating chamber then you can feel the pressure against the wall of the chamber which is identical to that of gravity only the cause is different , now did we nailed it ? :D

Janus

When you are "standing" on the inside surface of the cylinder you share the tangential velocity of that part of the cylinder. If you jump up, you still keep that velocity. for someone not spinning with the cylinder you will travel in a straight line at a velocity due to the vector addition of your jump velocity and the tangential velocity. This straight line intersects the cylinder wall at two places, one being the point at which you jumped. The other will be some distance in the direction the cylinder is spinning.

Since the cylinder is spinning, the physical spot from which you jumped will be rotating into a new position while you are in the air. In fact, it will move to almost exactly the same point where your straight line trajectory will intersect the cylinder. To you, it appears as if you jumped straight up and came down back in nearly the same spot. (how close you come to landing in the same spot depends on the radius of the cylinder and how hard you jump.)

Doc Al

The cylinder walls (and you) are accelerating towards the axis of the cylinder.
Since you are in a rotating reference frame, inertial forces are introduced. If you drop a ball, it will act as if a force pulled it toward the wall. This is described as being a centrifugal force, which is an artifact of being in a non-inertial, rotating reference frame.
Huh? Looked at from an inertial frame, you are accelerating towards the center of the cylinder; it is the cylinder that provides that centripetal force. Viewed from the rotating frame, which would be quite natural if you were the one in the cylinder, you are not accelerating so the centripetal force (the upward push from the wall) and the centrifugal force would balance out. Nothing to do with zero gravity or LaGrange points.

stevendaryl

I would the analogy is that floating in the spinning chamber feels like being in freefall or in orbit in a gravitational fields (meaning: you don't feel anything), and that pressing against the wall of the spinning chamber feels just like being pressed against the floor in a gravitational field. My point is that what you really feel (whether in gravity standing on the floor, or in a spinning cylindrical chamber standing on the wall) are the normal forces pressing on you from the wall/floor.

fivetide

Ahh that makes total sense theoretically then if you stood on the inside of the cylinder rotating and suddenly the cylinder decided to disappear you would be flung out into space in a perfectly straight line and therefore the force I'm trying to get to grips with is constantly attempting to throw you in a straight line but the cylinder wall is causing you to stop. Thank you very much all of you who have contributed to this thread.

However birds would have a hard time flying ? lol :)

Crazymechanic

In a medium with no oxygen i think flying would be the least of their problems... :D

Well finally after many posts you got it.I guess sometimes you get the picture after a certain well put analogy or situation.

jtbell

Why would they have a centrifuge on the International Space Station if it doesn't work?

http://www.spacesafetymagazine.com/2...fuge-facility/

fivetide

? I said it "would" work :)

"I understand that they use centrifugal force to adjust the international space station; I can understand this working, as a space station has a certain amount of attraction to the Earth in other words sharing its gravity."

Doc Al

I'd say you do not understand it at all. There's no "sharing" of gravity.

fivetide

Your right... however they share an attraction? Each attracts the other, gravity being the attraction therefore sharing gravity ?

Doc Al

Nope, nothing to do with gravity.

Emilyjoint

one point to note: The force due to gravity does not require physical contact, it is a force between objects even when there is no contact.
The force experienced in circular motion requires contact between the object and the wall (floor) of the space station. If the object has no physical contact with the floor then there is no force.

Crazymechanic

good point Emilyjoint , that's a distinct feature of gravity the field it has, while centripetal is rather a phenomenon of physical objects or matter to always travel in straight line and when forced to rotate in a circular path creates a pressure on the wall because it is trying to go straight.