This one irritates me even more...

Well......if i'm sitting it space all alone with this string and lead it's speed and inertia might be different the basic laws still apply. That's all i ment by it has nothing to do with gravity.
 
Oh, sorry Hex. I misunderstood. Evidently, some of the stuff I learned 20+ years ago in college is wrong. Not really surprising though. I think I have to stick with the physicists on this one. I included that link to show you that that information is still out there. Of course, it was in an encyclopedia, not a physics text. Damn, you're going to make me spend time learning what else has changed in physics. I did understand that in a spinning space station it is centripedal force that gives the illusion of gravity.:D
 
Now there's a question I always have trouble with. In general, if you prove something to me, I accept it. If however I can "feel" the gravity on a space station, how can it be an illusion. Maybe I think too much.:retard:

Ooops... What If god is an illusion?
 
chcr said:
If however I can "feel" the gravity on a space station, how can it be an illusion.
Click to expand...

Gravity is a force exerted by one mass on another. You feel a force acting on you in the spinning spaceship, but it's not a gravitational force, it's the centripetal force caused by the circular motion.
 
hex is correct, centrifugal force doesn't exist. There is only inertia of an object, and the centrepital force developed in any connection that accelerates that object (forces it to follow a circular path).

chcr, Einstein's general relativity describes the relationship between an accelerating reference frame (spinning space station with "simulated" gravity) and a reference frame in a gravitational field ("real" gravity produced by the mass of an object).

Um... I don't think I'm even going to attempt to explain it. It takes a book to make it clear.
 
Ardsgaine said:
Gravity is a force exerted by one mass on another. You feel a force acting on you in the spinning spaceship, but it's not a gravitational force, it's the centripetal force caused by the circular motion.
Click to expand...
outside looking in said:
chcr, Einstein's general relativity describes the relationship between an accelerating reference frame (spinning space station with "simulated" gravity) and a reference frame in a gravitational field ("real" gravity produced by the mass of an object).
Click to expand...
I was being facetious, I meant it as a joke. Hex actually made his point (re. centrfugal force) very well. It just isn't what I learned in college 25 or so years ago. I was an engineering student with a minor in astronomy, so I had quite a bit of physics. As it turns out, that is far from being the only thing I need to "unlearn" as I have the lesiure. You know, I have a book on physics that someone gave me while I was in college that was written in the '50s. It was about as out of touch with mid-seventies physics as I am now. Just something for you guys to look forward to.:D
 
chcr said:
I was being facetious, I meant it as a joke. Hex actually made his point (re. centrfugal force) very well. It just isn't what I learned in college 25 or so years ago. I was an engineering student with a minor in astronomy, so I had quite a bit of physics. As it turns out, that is far from being the only thing I need to "unlearn" as I have the lesiure. You know, I have a book on physics that someone gave me while I was in college that was written in the '50s. It was about as out of touch with mid-seventies physics as I am now. Just something for you guys to look forward to.:D
Click to expand...

whew! Man, I was sweating bullets comtemplating the prospect of trying to explain general relativity in some semi-intelligable manner. :D

You know... I've probably read a dozen books on string theory, astronomy, cosmology, quantum physics, etc. in the past two or three years, and guess what? I'm out of touch with modern physics as well. It's amazing. By the time a scientist takes the time to write down a book, have it proofread and revised, published, make it to the shelf, me take notice and purchase it, and then take the time to read it, physics has nearly made obsolete what I'm reading about. Of course, it's usually the case that I'm reading about gobbledygook theories, and they are only replaced by more gobbledygook theories, so I suppose all is well and I'm not really missing that much after all. :D
 
BTW, what field of engineering is your education and profession? I went the mechanical route... always a tinker and gearhead. :)
 
outside looking in said:
BTW, what field of engineering is your education and profession? I went the mechanical route... always a tinker and gearhead.
Click to expand...
Hope your not disappointed, but I dropped out of Cornell in my second year to play in a rock and roll band (musicians get laid a lot more than engineering students). Never went back. I had a free ride too, National Merit scholarship, and I won a big mathematics award. The only thing I had to pay for was books. Since then, well I read a lot, try to keep up with astronomy some and complain about all the idiots in the world.
As for what I do, I keep up 15 PCs and a Digital server that serves 15 tire stores plus all the dumb terminals attached. I'm thinking about taking the A+ test, but I'm not sure it would pay for itself.
Oh, it was mechanical engineering, but like I say, I didn't even finish two years. I've always been a serious gearhead though.
 
chcr do you have an active hands on interest in astronomy? Just curious. I used to be a die hard and sit up all night with my 3" Unitron and 10" Meade. Do you have or have you ever had your own scope?
 
Made my own 4" reflector at one time, don't have one now. Not very active any more unless you count looking at the sky on clear nights.
 
Response #: 1 of 1
Author: Sam Bowen
Text: Yes, this idea does have a sound meaning and valid existence. It
does not represent a "real" force in the sense that Newton uses, which is:
something that gives rise to accelerations in a reference frame which is not
rotating or being accelerated (a frame in which objects at rest tend to stay
at rest unless acted on by a force) (these frames are called inertial frames).
However, in a rotating reference frame (or coordinate system) such as a merry
go round, objects that are at rest tend to slide and objects with no "real"
force do not move in straight lines. Have you ever tipped over a glass full
of liquid in a turning car? From the point of view of the rotating coordinate
system what tipped the glass over is the "centrifugal force". From the point
of view of the inertial frame of reference outside the car, the glass was
still trying to go forward in a straight line when the car turned and the
force acting on the bottom of the cup flipped it over. Both perspectives are
valid and you can calculate the results from both perspectives as dictated by
convenience, but there is no "real" force of this type. It is however very
useful to think this way.
Click to expand...
I thought this was rather an interesting take.
I also found something else that made the "imaginary" force problem clear. A "force" does not cause motion, it causes acceleration. The object being acted upon by "centrifugal force" does not accelerate, it is simply trying to stay in motion in a straight line (Newton's First Law, interestingly enough).
 
Yeah, it is a somewhat convient way of thinking about it if you're in an accelerating reference frame, and that's why its existence has continued.

The problem is that equating centrifugal force as the opposite of centrepital force (as some attempt to do) can only be done if the two reference frames are relative inertial frames (the requirement for special relativity). Accelerating reference frames are not relative to inertial ones, hence the equalivalence breaks down.

What tips the glass over is inertia, not a force, but I guess it helps people to think of it the other way.
 
outside looking in said:
What tips the glass over is inertia, not a force, but I guess it helps people to think of it the other way.
Click to expand...
Yep, once I understood it, it seemed so obvious.
 
Now that you people know the truth i expect you to stick to it. Whenever you Sehen Sie a scientist you must keep him in line. They werden Sie nicht get away with this deceit!wir werden them into submission.Sie glauben der Spitze unserer Klingen!. und wenn sie nicht einwilligen, zerstören wir sie alle!
 
You must log in or register to reply here.
Back
Top