[SteveFish]

Geezer, with your doughnut hole within a massive structure there wouldn't be the Coriolis effects I described. Regarding your fair ride, this sounds like the barf express to me. Steve

[Geezer]

Geezer, with your doughnut hole within a massive structure there wouldn't be the Coriolis effects I described.

Agreed. The two people at the ends of the rope test would yield a similar result. They would not rotate relative to the cylinder.

Re. the "amusement" ride, as I remember (it was a very long time ago and I vowed never to go back on one) it was more about abject terror than nausea. Maybe fear suppresses the upchuck response, but that's probably a matter for a different thread.

EDIT: Now I'm completely confused. I'm not sure whether this proves the existence of centifugal forces or not  []

[SteveFish]

Geezer. A physicist will tell you that the guy swinging the weight is pulling a moving weight into a circle, the weight is not doing the pulling. Here is an analogous imaginary situation. If you were in an enclosed space on the back of a device that can move slowly and very smooth such that you can't tell that you are moving. You are holding a rope that runs through a hole in the wall that is tied to a heavy weight. Your perception when you are moved by the device is that something is pulling on the rope when, in fact, you are pulling the rope. In your frame of reference the force is real, but it is in fact a fictive force from the frame of reference outside of the imaginary device. Steve

EDIT- I fixed the post to your satisfaction, but you are awfully sensitive. It was only an observation because you keep attributing a lot of importance to the centripetal/centrifugal terminology when it is really no big deal and was laid out by Newton, the inventor of both terms. The Coriolis force is also a fictive force and it is quite useful when trying to understand weather. It is all a matter of ones frame of reference and, for example, the Einsteinian viewpoint of Newton's gravity relegates it to being a fictive force.

[Geezer]

Geezer, you are attaching a little too much importance to this.

Steve,

I think it is rather presumptuous, and extremely patronizing, of you to try to decide how much of anything I am attaching. It's also presumptuous of you to decide what a physicist will tell me, unless of course you are a physicist, in which case you might say "As a physicist......

If you would be good enough to rephrase your post minus the supercilious editorials, I'll try to understand what you're waffling on about.

[Geezer]

Thanks Steve.

Lest you misunderstand, I am only being sensitive on behalf of TNS members in general. Were it not for the rules of decorum here, the boot would be firmly on the other foot.

Believe it or not, some people actually visit this site to learn stuff. They don't expect to get a telling off from some supercilious twit.

[SteveFish]

Geezer, you are maintaining decorum by calling me a supercilious twit? One difference between you and me is that I don't take offense at all. I simply don't care what you think of me unless you catch me making an error of scientific information, then I would be very upset with myself and apologize (which I have done here). I am actually a little concerned with this site regarding expertise and accuracy. I have participated in some sites that are run by very high level scientists, and I think you would be much more than a little surprised at how rough communication can get when there is a poster suffering from the Dunning Kruger effect. Steve

[Geezer]

See, there you go again. You inferred that I was calling you a supercilious twit. I didn't.

Meanwhile, returning to the topic, if I understand what you are saying, centrifugal force is merely a name we (and Newton) attribute to the reaction caused by (the real) centripetal force. I think I may have tried to point that out about ten posts ago.

[SteveFish]

I don't think that calling centrifugal force just a name, while the real force in this situation is centripetal, is a very good understanding. This is because you would also have to agree that centripetal force is actually just a name because distortion of space time in some instances, according to general relativity, is the real force. They both are just terms in formulas that depend upon ones frame of reference. Further, if one wants to talk about these things it is important to state the frame, hopefully the most appropriate one, and be consistent with it.

As for misunderstanding what you said, it is really quite clear and I don't think anybody would disagree with me. Next you are going to say "if the shoe fits, wear it." I know how to play the "you didn't read what I said" game. You should be ashamed.

[Geezer]

If we want to help people learn and get a better understanding of mechanics and dynamics, I think it's best to avoid the use of terms that can lead to misunderstanding.

I think there is a common misconception that "centrifugal force" is a force that will cause a rotating body to "fly off" at right angles to its direction of travel. Of course, we know that is not true. As soon as the centripetal force is removed, there is no centrifugal force, so why not simply call it what it is i.e., a reaction to centripetal force?

Of course you are right in saying that this is only one model that we use to describe circular motion, I just happen to think it's best to be as clear and consistent as possible within that particular model.

I will refrain from commenting on your obvious reference to Dunning Kruger.

[SteveFish]

Geezer, what you say is very sensible because centripetal force is the best and most accurate explanation in our common everyday frame of reference. I tend to correct people who use centrifugal force in everyday usage, especially when it is leading them astray on what they are talking about. But in fact, there are technical uses of centrifugal force that are useful, just like the term Coriolis force is useful in many circumstances. Steve