That ^ is what I was trying to say to start with, in a round about kind of way. This is (partly) why Todd is making a very cool driving sim, and I am making renders and hot air. The other main aspect is that he can code and I can't, but even if I could I doubbt I could do what he does.

Well said. I did get carried away on stressing whether g is a force or an accel, but I'm done talking about that.

Ok, allow me to chip in a few. Since titles are being thrown about in this thread, let me state for the record that I have a Ph.D. in physics, and I work in theoretical physics.

It was one of the great mysteries of classical physics as to why apples fall as fast as cars off a cliff (in vacuum, and forgetting there were no cars at the time). While the Newton's gravity formula shows that such behaviour is indeed the case, it is a mere postulate without any explanation. The fact as to why the mass entering the forumula for gravitational force and the one entering the acceleration formula (F=m*a) are the same (the so called gravitational and inertial mass equivalence) was unexplained.

Enter a bright young lad named Einstein. He observed the same as what we are arguing now, namely that one really can't sense properly whether it's the effects of gravity one is feeling or if it is acceleration. He actually had the light bulb moment upon realizing that free falling is basically the same as being weightless. A bit of mathematics later (well, that was the crucial, hard and time consuming part) and he was able to show that starting with the ideas of special relativity and, importantly, equivalence between gravity and acceleration one can explain the gravitational force (as per Newton) and also go beyond that, predicting phenomena that have subsequently been tested to be true. Gravity is interpreted as being due to curvature of spacetime. This theory goes by the name of general theory of relativity and is still largely baffling even the smartest physicists, as noone knows yet how to merge it with quantum stuff.

While the whole discussion is really semantics and somewhat metaphysical (theories taken at face value are there just to predict stuff, giving them more meaning borders on religion), the simple fact that such a simple premise that Einstein took can yield so much more insight than previously imaginable, shows that there is some merit to the idea that, indeed, gravity is acceleration. More precisely, standing still in a gravitational field is the same as accelerating upwards with no field present.

So Todd, your hunch was a rather good one all along, seeing it lead to great ideas in the past. Of course, you had it easier, as Einstein didn't have high performance cars to drive and check those effects more easily . See you in Vienna soon!

Now let's discuss about TSC and ABS, m'kay?

http://www.weebl.jolt.co.uk/comics/tv.swf

Stay zen guys.

Quote from Hyperactive :

Now let's discuss about TSC and ABS, m'kay?

okay, don't have them in Real Life(tm), don't need them in LFS. I actually don't want them in LFS (at least in the race cars), because I don't know any race series, that uses ABS, and only the formula 1 with TCS (and they will ban it soon )

please don't flame me

I'm not going to flame you. I'm going to support your view.
ABS sucks, TC sucks, I don't want LFS to suck. That easy.

Vain

Quote from herki :

okay, don't have them in Real Life(tm), don't need them in LFS. I actually don't want them in LFS (at least in the race cars), because I don't know any race series, that uses ABS, and only the formula 1 with TCS (and they will ban it soon )

please don't flame me

Fair enough. I certainly don't want them to be included purely as driving assists.

But: There are lots of cars that use these things IRL. Certain race series' use them, or variations of them, too. For instance, many (if not all) Porsche Cup series' use cars still equipped with ABS.
If any further real cars/racing cars that are included in LFS are IRL equipped with these "assists" then I would not be averse to these things being simulated also.

All of this is comming from a mouser.

I have learnt to be able to deal with the on/off nature of the throttle, and the brake in LFS, as both can be cured with a good setup, and a good driver. It really comes down to this. Do you want the new guys to be able to race with the big guys? Make the learning curve not so steep. I think that if you race with ABS and TC then your not racing to your full potential. But at the same time, I would also love to see TC, has it will help me learn new tracks faster, and show me what is really capable out of the car from the get go. The same is ture with ABS it will show you have fast you can go around turns, how late you can break. What your laps times can be. But all of this are just shortcuts. It might take longer to get the best time, but you will still get your best time. I lap tracks like Blackwood only a second off the World Record. Its not to hard for mousers to learn how to race, if they take the time to do it.

Quote :

only the formula 1 with TCS

Some of the race series that allow traction control:

FIA - F1
FIA - GT1
ACO - LMP1, LMP2, GT1
IRL - (driver adjustable)
ALMS - GT1
Pro Formula Mazda (think Indy lights car)
Dutch Supercar Challenge (power/weight ratio determines class, otherwise no restrictions)

Quote :

No traction control - It might take longer to get the best time, but you will still get your best time.

Best lap times will always be better with a good traction control system. Modern traction control systems allow for optimal slippage of the tires instead of just stopping the slippage. The ones that use individual wheel braking and engine management (power control) do the best job, but aren't allowed in all the racing classes that allow traction control. Many classes restrict traction control to engine management, but these still allow for controlled slippage, something that no driver can do consistently, especially for the duration of a full race.

I suggest you do a web search for "traction control race" to get more info on this. Real life drivers aren't ashamed to use traction control, as their goal is the fastest and also safest lap times.

Champ car (formerly CART - mostly road courses now) and NASCAR (almost all ovals) are the main high end race classes that don't allow traction control, along with the controversy of which teams are using "hidden traction control".

Quote from GregorV :

See you in Vienna soon!

Sausages or RL public showing?

Thanks for insightful post.

Quote :

equivalence between gravity and acceleration

It should be explained that this equivalence relies on an imaginary constant strength gravitational field, one that could be produced by an infinitely large flat plane.

In real life, gravitation fields are effectively generated by point sources, and diminish in strength the further away from the source you get. For a real world point source, the strength diminishes with the square of the distance. For an imaginary infinitely long line source, it diminishes with the distance (not distance squared), and for an imaginary infinitely large plane, it remains constant.

In real life, you can tell the difference between gravity and acceleration by checking to see if the force varies with position. If it varies, then there is some component of gravity involved.

Quote from JeffR :

Because of the engine's torque, one tire will get more downforce than the other. Viewed from the rear, most engines rotate counter-clockwise, with the resulting torque creating a bit more downforce on the left rear, which causes a slight yaw to the right. However since both tires are spinning fast, grip and forces are low, and it's not very much of a yaw. (LFS yaws the cars left). Do a websearch for "burnout contest videos" and you'll see some good examples of control with both rear tires spinning at high speed. LFS doesn't model this.

Ok so we can draw from that, that it is most likely the tyre modeling issue, and Scawen is working on that now... while there is any issue with tyre modeling, I'd have to assume that simulating any form of traction control would also have potential to operate in unexpected ways, and once the tyre modeling issues are sorted out there is less need for traction control

Quote from GregorV :

Ok, allow me to chip in a few. Since titles are being thrown about in this thread, let me state for the record that I have a Ph.D. in physics, and I work in theoretical physics.shows that there is some merit to the idea that, indeed, gravity is acceleration. More precisely, standing still in a gravitational field is the same as accelerating upwards with no field present.

You have a phd and you say these things? You remind me of a postgrad here who insist that the pronounciation is "armstrong" and not "angstrom".
If you stand still in a grav field, you are not accelerating. There is gravitational pull on you, but you are not accelerating.
when you are not in a grav field and you are accelerating, yes, you are accelerating because there is something pushing you forward. In this case you feel the pressure on your back, in the same way you feel the pressure onyour feet when you are standing on earth. But that course of thinking does not mean that gravity is the same as acceleration.

Gravity is one thing. It is the name of one of the four fundamental forces in nature. Weak interaction, Strong interaction and electromagnetism being the other three.
Acceleration OF gravity is another thing. Have you ever heard saying "electromagnetism" is an acceleration? no. it is a force. But you can indeed accelerate DUE to electromagnetic forces.

Tristan, the argument that gravity is acceleration because we write 1g=9.8m/s^2 is silly, because in that case, 1g is not exactly "gravity" but "acceleration due to gravity". F=m*a -> Gravity = mass * acceleration_due_to_gravity (but NOT "gravity")
.

It is the most common logical fallacy. "energy causes force therefore energy is force". no.

Quote from JeffR :

It should be explained that this equivalence relies on an imaginary constant strength gravitational field, one that could be produced by an infinitely large flat plane.

In real life, gravitation fields are effectively generated by point sources, and diminish in strength the further away from the source you get. For a real world point source, the strength diminishes with the square of the distance. For an imaginary infinitely long line source, it diminishes with the distance (not distance squared), and for an imaginary infinitely large plane, it remains constant.

In real life, you can tell the difference between gravity and acceleration by checking to see if the force varies with position. If it varies, then there is some component of gravity involved.

There is no equivalence. None. No equivalence. Gravity is a forcefield. A phenomenon where if you put something of mass (either still or moving, photons) in its area, there is force happening on that mass. Gravity is a force. Acceleration is the phenomenon where the velocity vector changes with time.

Saying that gravity IS acceleration or that it is similar in any way is VERY WRONG.

Look at you right now. are you accelerating? NO. you are NOT accelerating. your velocity is ZERO and it STAYS zero. if gravity was acceleration then since you are not accelerating, gravity would stop to exist. but gravity STILL exists. you still feel your weight, because you feel the ground underneath you. but you are not accelerating.

for fscks sake, open a book, open your eyes and open your mind.

Amazing... The gentleman you're arguing with indeed has his Ph.D in physics (chaos theory) and is an author of the following papers. I believe the first one is his Ph.D thesis, but could be mistaken.:

"Faster than Lyapunov decays of classical Loschmidt echo"

"Classical Loschmidt echo in chaotic many-body systems"

Somehow I'm not surprised he currently teaches physics at a university in Slovenia. Ah well, perhaps you can teach him a few new things about gravitational acceleration versus gravitational force anyway while clearing up any misconceptions he might have about General Relativity illepall

Either way, have fun

i don't care.

we are not talking about GR here. we are talking about simple concepts, motion, forces and acceleration.

Suit yourself

Edit:

Ok, I had to come back and amuse myself.

Here's what was said that got me into this discussion:

Tristan: (Force Dynamics comes closest, but it's only 1g sustained,

You: No. It can not exert sustained acceleration. To feel any kind of acceleration on yourself, you need to MOVE.

I said it wasn't necessary to move. Just pop your feet up in the air and you will feel exactly as though you were accelerating at 1g. I meant "forward," but didn't say so. I figured everyone would understand that, and they did, with the exception of yourself

You don't have to move at all to feel an acceleration. If you're stationary in a gravitational field you feel exactly as though you are accelerating. You are right now, "feeling an acceleration" straight upwards. Are you literally accelerating? Outside the context of 4D space where most of us spend our intellectual time, no. I agree. Your position isn't changing so you aren't accelerating. Nobody is arguing that.

However, you are indeed "feeling as though you were accelerating" at 1g. (Is it ok if people use the term "feel an acceleration" there? According to GR that's just fine because it really winds up working out just like that. You'll learn that later in school hopefully.) I.e., if there were no gravity and you were pushed upwards at 1g, it would feel exactly the same as if you were sitting on Earth, not accelerating at all. And in the latter case, there is no movement. So the statement you made in reference to a motion platform that sits at an angle to give the impression of forward/rearward/sideways sustained acceleration:

"It can not exert sustained acceleration."

Is sort of correct if taken literally word for word, although if you want to split hairs you don't "exert" an acceleration so the statement is meaningless. But I wasn't going to be anal and pick apart your sentence. I understood what you meant and just carried on.

Anyway, the next statement you made:

"To feel any kind of acceleration on yourself, you need to MOVE."

Is categorically false for the reasons given. Remember, the verb there is "feel." I.e., "to feel as though one is accelerating," not to literally be accelerating.

What's most amusing to me about this whole thread is that the people that know nothing about physics at all, or know less than you or I or Dr. V. over there might, understood this immediately.

"To accelerate you need to move"

Yes.

"To feel any kind of acceleration on yourself, you need to MOVE."

Nope. I am feeling exactly as though I were accelerating straight up at 1g in the absence of gravity right now and I'm not moving anywhere.

The tilting motion platforms are a snazzy idea because they can make you feel as though you were sustaining an acceleration of some kind in the direction of interest.

Tee Hee. But I think we might need to let him be Todd, cos his head will explode.

<poof>

Moral of the story, being anal about a definition does not help the disussion

George,

first of all, knock it off with insults. Second, be mindful of the phrase, "a little knowledge is a dangerous thing." I am in awe almost every day as to the things I still yet have to learn about, and not for one second have any Faustian beliefs that I already know all the knowledge in the world. Choose to do otherwise at your own academic peril.

It is no way to argue that we are not talking about GR here. It is slightly metaphysical concepts we are debating (as an apple will always fall with 1g regardless of whether we assume gravity is an acceleration or a force) and to build any sort of philosophy on science one needs to look at its most fundamental theories. Just as concepts of determinism shatter when employing quantum mechanics (whereas in Newtonian physics the future is in principle exactly determined from the exact starting conditions, barring concepts of chaos), general relativity turns our concept of gravity, space and time on their head.

In general relativity, the space shuttle is said not to be in accelerated motion in orbit around the Earth, but that it is rather following a straight line through curved spacetime. As such it is locally not experiencing any acceleration. It is conceptually much simpler to describe motion that way, even if it is counterintuitive. If such a description also helps understand other phenomena like the peculiarities of the trajectory of Mercury, then the theory is surely to be considered more fundamental than the one preceeding it. Occam's razor will get you anytime.

And gravity is NOT just like one of the other fundamental interactions. All the other interactions take spacetime as the underlying concept which they are formulated upon. Gravity on the other hand is responsible for the very behaviour of spacetime. Attempts to write down (quantum) gravity as a similar field theory to other interactions did not yield any tangible results so far, although they produced a lot of interesting mathematics on the side (string theory). It is precisely because gravity is unlike anything else that this remains one of the large open problems of theoretical physics.

Kidcodea, actually, I am going to Vienna to assa..... err discuss things with Todd as he ... knows ... too ... much.

Todd, nah, those are just my latest papers, I almost forget what I did in my Ph.D. thesis .

i do not have a phd. i do not have a master's degree. i do not have a BSc. i am still a pregraduate. i have not studied general relativity, only special relativity.
i did not insult anyone. but it is insulting to say that gravity is acceleration.

Wow, this thread is fun. I tend to the view that the fundamental essence of what gravity is isnt exactly germane to the discussion, but I think its NOT an acceleration that causes a force, but it is probably either a force that causes and acceleration, or even a field that causes a force that causes an acceleration, but whatever.
What we are talking about is perception, so I'm going to take issue with something the esteemed mr. Tseros said:

Quote :

when you are SITTING on your ASS, the earth PULLS YOU DOWNWARDS.
it exerts a FORCE on you.
the CHAIR on which you SIT exerts an OPPOSITE FORCE on you and thus you STAY STILL.

THE NET SUM OF THE FORCES YOU FEEL IS ZERO
NADA
ZIP
NULL
0

you are NOT ACCELERATING.
you are NOT MOVING. (relative to ground)
you are NOT EXPERIENCING ACCELERATION.
your VELOCITY IS VECTOR 0
your ACCELERATION is ZERO
a=f/m =0 since f_total on you is ZERO. if you consider only the gravitational pull, yes, a=1g but that is WRONG because there is also the force from the CHAIR. otherwise if you write a=1g that means you are accelerating towards the GROUND, THROUGH the chair INTO the ground.

Okay then, try this one:

You are floating in space a billion miles from the nearest object of any mass.
THE NET SUM OF THE FORCES YOU FEEL IS ZERO
NADA
ZIP
NULL
0
you are NOT ACCELERATING.
you are NOT MOVING.
you are NOT EXPERIENCING ACCELERATION.
your VELOCITY IS VECTOR 0
your ACCELERATION is ZERO
a=f/m =0 since f_total on you is ZERO

Now are you telling me that a human being with their eyes shut cant tell the difference between sitting on a chair and floating in space?

You seem to believe that a human being is a point object of infintestimal size. The net sum of forces when sitting in a chair is zero, but the force diagram is of a big reaction force poking us up the ass, and then trillions of little downward forces on every particle of our body setting up moments and shears in our muscles, bones, nerve ending etc. all of which are sensed by us.
So the way force dymanics et al work is to just use the 1g force provided by gravity to set up a body force diagram very similar to that experienced during the events being simulated. I cant really understand what all the confusion is about to be honest.

Ooh, and here's the clincher folks
From wikipedia... Equivalence_principle

Quote :

...Albert Einstein's assertion that the gravitational "force" as experienced locally while standing on a massive body (such as the Earth) is actually the same as the pseudo-force experienced by an observer in a non-inertial (accelerated) frame of reference...
That is, remaining at rest in a uniform gravitational field is physically equivalent to experiencing an acceleration (e.g. being at rest with respect to the Earth, while under the influence of its gravitational field, is an accelerated state of motion).

So y'know, if Einstein said that being accelerated and standing on earth are equivalent, perhaps we should all just accept it and get on with our lives