Beam Axles - Front, Rear or both.

[Z]

Can't remember if I've asked this before, but why do you talk about centrifugal force?

Jay,

Just calling a spade a spade.

A "centrifugal force" is the VERY REAL inertial force that pushes/pulls the driver, or the car, or anything else, outwards (ie. = "centre-fleeing") when going around a corner.

An interesting example of how far the Education system has spiralled down the S-bend is the fact that nowadays most Schools teach their students that such "inertial forces" are NOT REAL, or are FICTITIOUS, or have some other lame name to suggest that they are somehow lesser than the other "real" forces.

Is that what you are suggesting?

The really funny part is when you ask the, ahem, "Teachers" to explain their reasoning behind that ideology. Wow, such poor clarity of thought!!! (Followed by much on my part.)

If anyone cares to give their arguments for why "inertial forces" are NOT real, then please do!

Z

[Markus]

I'm not a teacher and honestly don't even care about todays education, but I'm bored enough to bite the bullet (this is not an answer to why inertial forces aren't real though, 'cause I consider them real, and there's nothing here you wouldn't know from before anyway).

Intertial forces are called fictitiuos (stupid choice of name IMO) because they are a "byproduct" of accelerating an object with mass into any direction, caused by the objects resistance to be accelerated. For example nothing "pushes" the car outwards when cornering, instead the car is resisting the acceleration caused by being pushed inwards by the tires, and trying to return to zero acceleration state i.e. landing in the woods.

If you draw a FBD of a car negotiating a corner, either centrifugal force "doesn't exist", Fy generated by the tires "doesn't exist" or your data acquisition is lying about the lateral acceleration of the car, because you can't have acceleration if the sum of forces is zero. In essence the whole subject is just a "flaw" of the system we use to simulate reality.


But I didn't pay that much attention in school, so I don't know the extent to which inertial forces were bullied...

[Jay Lawrence]

Fair enough. I just struggle to define a centrifugal acceleration, which means I struggle to understand how there can be a centrifugal force (separated from centripetal force obviously).

[Z]

INERTIAL FORCES.
===================

Jay,

If your car's velocity vector is to turn around a corner, then the car needs a centripetal ("centre-seeking") acceleration. Inertial forces are always in the OPPOSITE direction to the acceleration of a massive body, hence you car feels a centrifugal ("centre-fleeing") force.
~~~~~o0o~~~~~~

Intertial forces are called fictitious ... because they are a "byproduct" of accelerating an object with mass into any direction, caused by the object's resistance to be accelerated. For example nothing "pushes" the car outwards when cornering, instead the car is resisting the acceleration caused by being pushed inwards by the tires, and trying to return to zero acceleration state...

(My emphasis.)

Markus,

Thank you. Your explanation is similar to those typically given by today's Education system. Sometimes the emboldened words are replaced with "the body wants to...", or "has a tendency to...", etc., but otherwise with the same gist as yours.

I will now show just how ABSURD that kind of thinking is.

(Markus, please note that this is not directed at you, since you are simply repeating what you have been taught. This is directed at the failed Education system generally.)

Also, what follows is quite long, and has little to do with Beam-axles. It is mainly big-picture stuff, aimed at giving anyone interested a better appreciation of the quality of your current education.

And maybe it's a fun distraction from the ongoing Rules debates...
~o0o~

To aid my argument, first imagine this scene. You are lying on the soft, green, grass of a meadow. The Sun's rays, which are a form of Electro-Magnetic radiation, a system of "very real forces", gently warm you. The Earth's Gravity, another "very real force", gently pulls every particle of your body downwards. The contact forces between the ground and your lower body, which are again "very real EM-forces", counteract the Gravity forces. Aahhh, so relaxing...

Except that a short while ago you were enjoying a scenic balloon flight. Unfortunately, being a high-spirited student, you were goofing-off and accidentally fell out of the basket. For a short time you experienced a very pleasant period of "free-fall", where you felt almost no forces acting on your body at all. Just a gentle wind...

But then ... a very sudden upwards force from the ground subtracted speed from your, by then, quite large downward velocity. The end result of that short period of upward acceleration is that your body now looks like a super-sized pepperoni pizza!

BUT (!!!!!!) you know that things can only get squashed-flat like you now are, when there are TWO opposed forces squashing the things together. For instance, you can remember playing with that large hydraulic press in the FSAE workshop, and you know that stuff only gets squashed when BOTH the top AND the bottom plates of the press are pushing hard on the body, in OPPOSITE directions, and at the SAME TIME.

BUT (???) you also remember being taught that the ONLY "real force" acting on you a moment ago was the upward one from the ground. Err..., because that's the "very real EM-force". Apparently, there was NO DOWNWARDS INERTIAL FORCE whatsoever acting on your body, because those forces are NOT REAL!

So why is your body squashed so bloody flat!! And why does it hurt so bleeding much!!!
~o0o~

Let's use reductio ad absurdum to show how silly your teachers are. We start by assuming that the standard argument above (ie. in Markus's quote) is a VALID one. We now apply that reasoning to different situations.

1. When an apple is ripe enough, it releases its EM bonds with its tree, and accelerates downward toward the Earth.

But, according to M-reasoning, this common natural phenomenon has nothing to do with a "real force of Gravity". This is because we choose to call the concept of Gravity a "fictious force", which is to say, it is UNREAL!

Rather than being the work of a "real force", we say that this phenomenon is simply a "tendency" that apples have, whereby they "want to", or are always "trying to" (to use the correct M-terminology) get closer to the Earth. Similar "tendencies" afflict all massive objects, even big ones like the Moon that is always "trying to" get closer to the Earth.

We say that all these phenomena are just "by-products" of the relative positions of different bodies that have the property of mass.

Therefore, we have "proved" that Gravity is NOT a real force.

2. When a compass needle is turned to face East, and then released, it swings around to again face roughly North.

Again, this has nothing to do with a "real Magnetic force", because Magnetism is a "fiction", and is NOT a real force at all. Instead, those sorts of phenomena are simply something that compass needles "try to" do. They are a "by-product" of electrically charged particles moving in circles, or something like that.

Likewise, all those electric motors that misguided FSAE students use DO NOT generate any "real forces" at all. All those observable phenomena of E-cars scooting around racetracks are just "tendencies", and "by-products", of stuff "trying to" behave in certain ways.

Therefore, we have also "proved" that Electro-Magnetism is NOT a real force.

3. Similarly, we can "prove" that the Strong and Weak-Nuclear forces, or any other phenomena that anyone cares to describe as "a real physical force", is NOT REAL. We simply call them "tendencies", or "by-products", or some such...

So, are we making progress?

Summing up here, the standard arguments for why "Inertial forces" are NOT real, can be equally used to "prove" that none of the other forces are "real" either. Or, looking at it from the other direction, exactly the SAME arguments that are used to prove that Inertial forces are "UNreal", are also used to show that other forces ARE "real"! This is an ABSURD approach to reasoning, and we should try something more sensible.

If it walks like a duck, and it quacks like a duck, then call it a duck.
~o0o~

What can we classify as "real physical forces"?

Example 1. When the prices of things go up and down, the phenomena is said to be the result of "market forces". Unfortunately, the whole process is rather complicated, and it is very difficult to accurately, and consistently, predict future results from some reasonably simple theory. So maybe better to call these phenomena the process of "supply and demand pressures" (ie. because the word "pressure" is so frequently abused in its meaning).

Example 2. In Springtime, when boys show a "tendency" to bump into girls, the phenomena is referred to as "the force of love". Unfortunately, this whole process is very complicated, and it is all but impossible to accurately, and consistently, predict future results from some reasonably simple theory. So maybe better to call this phenomena "hormonal urges", or some such...

Example 3. When particles of stuff that have something called "electric charge", which can be either "positive" or "negative", are placed in a certain POSITION relative to each other, then they "try to" either move closer together, or move further apart. These phenomena are said to be the result of "Electro-Static forces". They can be very accurately, and very consistently, predicted with a very simple theory. So, yep, this is a good contender for a "very real physical force".

Example 4. When the above charged particles are moved at certain VELOCITIES relative to each other, then they "try to" change their relative velocities in certain ways. These phenomena are said to be the result of "Electro-Dynamic forces" (or sometimes "Magnetic forces"). They can be very accurately, and very consistently, predicted with a slightly more complicated theory. So, yep, another good contender for a "very real physical force".

Example 5. When particles of stuff that have something called "mass" are placed in a certain POSITION relative to each other, then they always "try to" move closer together. These phenomena are said to be the result of "Gravitational forces". They can be very accurately, and very consistently, predicted with a very simple theory (ie. in fact, very similar to Example 3 above). So, yep, another good contender for a "very real physical force".

Example 6. When any single particle of the above sort of stuff with "mass" is ACCELERATED relative to all the other such massive stuff in the Universe, then it always "resists" this change in its motion (to use M-terminology). These phenomena are said to be the result of "Inertial forces". They can be very accurately, and very consistently, predicted with an exceedingly simple theory (ie. the simplest so far, just "F => P-dot"). So, yep, another good contender for a "very real physical force".

And so on with the "Nuclear forces", where the theory gets a bit more complicated, but the predictability remains good.
~o0o~

Bit more coming (10k char limit!)...

Z

[Z]

INERTIAL FORCES (last bit...).
======================

So, what went wrong with Example 6 in above post? Why were Inertial forces given the cold-shoulder?

It seems to me that the problems started a bit over a hundred years ago. The following is a very abbreviated account.

In the 1800s there was much progress in understanding EM forces. Maxwell and others eventually developed the "field equations" of EM-theory. These led to a realisation that "light" was a wavelike EM phenomena. But waves like sound need a "medium" to travel through, and light was known to travel through a vacuum.

No problem, because "The Luminiferous Aether" was simply conjectured to be this medium. The concept of an ever-present Aether was around for much longer, even before Newton's Absolute Space. But then various experimentalists, such as Michelson and Morley, found that there was no measurable Aether-drift, namely no measurable shift in the speed of light due to Earth's movement through the Aether. Bummer!

In the first years of the 1900s, Einstein, ahem, borrowed Mach's ideas regarding relativity. These ideas were an attempt to abolish concepts like Newton's Absolute Space and the Aether. Einstein then stole Lorentz's, Poincare's, and others', work and presented it as his Special Relativity. Ten years later he stole Hilbert's maths and presented it as his General Relativity.

These two Relativity theories are fundamentally opposed to any ideas of an Absolute Space, or anything like an Aether. (Bizarrely, GR has at its very core a version of Galileo's Law of Inertia (= Newton's First), although in an unstated way.) But Einstein was a great self-promoter, SR and GR had a great marketing campaign behind them, and eventually they became The Absolute Truth.

So, even though SR and GR have some huge holes in them (eg. google "Twin's Paradox"), they are nowadays the only way that Modern Science is allowed to describe things at these macroscopic scales (QM is just for small stuff). And since SR and GR have no mechanism for explaining Inertial forces, it is the Inertial forces that had to be kicked out...
~o0o~

The twist in the tale.

The latest bit of populist science you students might have heard about is the "discovery" of the Higgs-Boson. Interestingly, while this discovery amounted to a few blips on a computer screen somewhere in Switzerland, many Scientists consider it rock-solid, 100%, iron-clad, proof of existence. Some are a bit more cautious. But its moniker as "The God Particle" certainly has a lot of people talking about it.

Anyway, the key point here is that the Higgs-Field is conjectured to give all other particles their property of Inertial Mass. That is, it gives everything a "resistance to acceleration". So the HF is very much a modern version of the Aether, or Newton's Absolute Space, or so on. Try googling Higgs + Inertia + Aether/Ether, etc.

Lots of other interesting stuff here, but I have waffled on too long. The key points you students might want to think about are:

Why is your Science Education so IDEOLOGICAL? That is, why is it a belief system remarkably similar to many religions, where you must believe what is written in some Gospels, even if those ideas are utterly ABSURD?

Will your Teachers ever admit that they were rather stupid to claim that "Inertial Forces are NOT REAL"? That is, will they ever admit that a hypothesis different to the one that they have hung their hat on, might now have more evidence favouring it (ie. the HF+)? Do experts ever admit that they got it wrong?

Will there ever be a return to WELL-REASONED discussions in Natural Philosophy? Or will the decline in standards continue?

Finally, are Double-Wishbone+Push/Pull-Rod&Rocker suspensions really The One and Only Absolute Truth? Are Beam-Axles really the work of the devil?

Z

[Markus]

Firstly, I want to apologize for not using "Z-approved" terminology. I'm not native in down-under, and I'm lazy enough to prefer using describing words to finding the correct words.

Secondly, this post merely continues the discussion about inertial forces or todays education system but criticizes the downward spiral of our forum discussion culture...

[B]INERTIAL FORCES.Markus,

Thank you. Your explanation is similar to those typically given by today's Education system. Sometimes the emboldened words are replaced with "the body wants to...", or "has a tendency to...", etc., but otherwise with the same gist as yours.

I will now show just how ABSURD that kind of thinking is.

(Markus, please note that this is not directed at you, since you are simply repeating what you have been taught. This is directed at the failed Education system generally.)

Also, what follows is quite long, and has little to do with Beam-axles. It is mainly big-picture stuff, aimed at giving anyone interested a better appreciation of the quality of your current education.

And maybe it's a fun distraction from the ongoing Rules debates...
~o0o~

[so long, read from post above]

Gravity causes acceleration in the body, inertial forces are caused by accelerating the body. Apples vs oranges, would have been more aid to leave your nice short novel to the table.

BUT (!!!!!!) you know that things can only get squashed-flat like you now are, when there are TWO opposed forces squashing the things together. For instance, you can remember playing with that large hydraulic press in the FSAE workshop, and you know that stuff only gets squashed when BOTH the top AND the bottom plates of the press are pushing hard on the body, in OPPOSITE directions, and at the SAME TIME.

It would be possible to "squash" the stuff with a hammer and without an opposing plate by hanging the object on a string and hitting it with a hammer. Thus the opposing force would be the inertial force and there would be acceleration to the body in each hit.

But the squashing is a bit different between the two: imagine hitting an apple with a baseball bat (inertial opposing force) and hydraulic press (direct opposing force). Or a superball.

Let's use reductio ad absurdum to show how silly your teachers are. We start by assuming that the standard argument above (ie. in Markus's quote) is a VALID one. We now apply that reasoning to different situations.

[list of three examples, see post above]

So, are we making progress?

Summing up here, the standard arguments for why "Inertial forces" are NOT real, can be equally used to "prove" that none of the other forces are "real" either. Or, looking at it from the other direction, exactly the SAME arguments that are used to prove that Inertial forces are "UNreal", are also used to show that other forces ARE "real"! This is an ABSURD approach to reasoning, and we should try something more sensible.

If it walks like a duck, and it quacks like a duck, then call it a duck.

I appreciate your use of latin, but the term you are looking for is straw man, not reductio ad absurdum.
Reductio ad absurdum would require an initially correct analoque and reducing it into absurdity.

What can we classify as "real physical forces"?

[Example 1-6 check post above]

Examples 1&2 are called fallacy of equivocation.
In examples 3-5 the contenders for force cause acceleration.
In example 6 the contender for force is caused by acceleration.

This still doesn't mean that inertial forces aren't real, but how they differ from the rest in this flawed system we're using.
Maybe an example of an inertial force causing acceleration would really stir this conversation up?

Will there ever be a return to WELL-REASONED discussions in Natural Philosophy? Or will the decline in standards continue?

I agree with this completely. To begin with please practice what you preach and please stop with the red herring and gish gallop (almost 2000 words, really?), it would result in a lot more (fruitful) discussions.

On a final side note, I'm not a huge fan of todays educational system either (even though it seems to be a bit better in Finland than Australia if Eric's blood pressure is an indicator of some sort) and would hope for more criticism towards it, however in a better constructed way compared to above...


Disclaimer: I did not consider the "vulnerability" of not using full quotes, so the original posts might or might not be like they were when I wrote this. Likely there's edits, so take this with a grain of salt.

[rwstevens59]

Gosh!!

And I thought I was just an old 'backward' mechanic who thinks about certain dynamic problems as frames from a film strip. Taking each frame, setting up an FBD of known conditions and then applying D'Alembert's principle to solve as a statics problem. Who knew!

All in jest, everyone!

Ralph

[Z]

Marcus,

Firstly, I want to apologize for not using "Z-approved" terminology....

My use of the phrases "M-reasoning" and "M-terminology" was a reference to your (Marcus's) quoted version of the standard Modern Education argument for "why Inertial forces are NOT real". As I noted, you have learnt this absurdity well.
~o0o~

Gravity causes acceleration in the body, inertial forces are caused by accelerating the body. Apples vs oranges...

Gravity does NOT always "cause" acceleration. You only have to stand on some bathroom scales to see that.

But, yes, Gravity and Inertial forces are different types of "real physical forces", so somewhat like apples and oranges are different types of "real fruit".

Also, in more formal discussions it is wise to say "... are conjectured to cause...".
~o0o~

It would be possible to "squash" the stuff with a hammer and without an opposing plate by hanging the object on a string and hitting it with a hammer. Thus the opposing force would be the inertial force and there would be acceleration to the body in each hit.

(My emphasis.)

Yes. That is exactly my point. And that is why Inertial forces hurt so much.
~o0o~

... the term you are looking for is straw man, not reductio ad absurdum.

No.

From my Dictionary, "reductio ad absurdum Latin. n. 1. a method of disproving a proposition by showing that its inevitable consequences would be absurd."

Which is exactly what I did. I assumed M-reasoning to be correct, then showed that its inevitable consequences are that NO FORCES ARE REAL, which is absurd (or, at least, pointless).
~o0o~

Examples 1&2 are called fallacy of equivocation.

No.

The word "force" can be used in many ways, such as "the force of law", "force of personality", etc. I was NOT misusing this ambiguity to try to prove a point. Rather, I was trying to find which if those many types of "forces" could be classified as "real physical forces". The first two examples are NOT suitable, the rest are.

I think the main problem here is that Modern Education doesn't do DEFINITIONS anymore. By contrast, open Book 1, Page 1, of Euclid's Elements and the first word is...
~o0o~

In examples 3-5 the contenders for force cause acceleration.
In example 6 the contender for force is caused by acceleration.

This still doesn't mean that inertial forces aren't real, but how they differ from the rest in this flawed system we're using.
Maybe an example of an inertial force causing acceleration would really stir this conversation up?

(My emphasis.)

The double-negative in there suggests that you think Inertial forces might be real, even though in your ME-indoctrinated M-reasoning you said that they are "fictitious". I sense a confused young man.

The small boy in you knows that the fall is NOT the problem, rather it is the sudden stop at the bottom that hurts. This is a matter of common sense, which all small boys understand.

But the educated young man has been so thoroughly indoctrinated in the belief-system that whenever there is any mention of acceleration, then all common sense must be abandoned, and you must believe that any pain at the end of the fall is pure FICTION!

And why the obsession with acceleration, and not position, velocity, electric-charge, etc.? (Rhetorical question, so think about it.)

(Or perhaps the confusion might be from Autumn-time hormonal urges... )
~o0o~

On a final side note, I'm not a huge fan of todays educational system either ...
... and would hope for more criticism towards it, however in a better constructed way compared to above...

When you eventually decide what seems more reasonable to you (eg. Inertial forces are real, or NOT real, or on any other ME-related subject...), then please post your thoughts here on the Forum. I think we all enjoy well-reasoned discussions. But try to avoid the mistakes above...
~~~~~o0o~~~~~

Ralph,

... dynamic problems as frames from a film strip. Taking each frame, setting up an FBD of known conditions and then applying D'Alembert's principle to solve as a statics problem.

Gee, wish I said it so sweetly!

Z

[rwstevens59]

I believe I warned you at some point Z, that I can't resist heavy sarcasm! It is part of my DNA.

Still working with, sketching and thinking about 2 DOF linkages. I'm getting there, just more practice needed.

Ralph

[Markus]

My use of the phrases "M-reasoning" and "M-terminology" was a reference to your (Marcus's) quoted version of the standard Modern Education argument for "why Inertial forces are NOT real". As I noted, you have learnt this absurdity well.

Which I find funny, as I have never even learnt these terms in english. Also it seems you didn't read my post at all but just used it as an excuse to your (beforehand composed?) post to question the educational system (well you did literally ask for it, which implies planning, "I bit the bullet" to see what you come up with).

In any case, using such references is pointless and even disobliging, especially when you're jumping into conclusions and implying I stated something I didn't actually state (feel free to read my post now). Oh, and by the way it's written with "k" (see note about glasses further down).

Gravity does NOT always "cause" acceleration. You only have to stand on some bathroom scales to see that.

But, yes, Gravity and Inertial forces are different types of "real physical forces", so somewhat like apples and oranges are different types of "real fruit".

Also, in more formal discussions it is wise to say "... are conjectured to cause...".

Yes, it doesn't cause acceleration when there's a normal force present. Do we also have to start playing stupid?

I'll keep that term "conjecture" in mind if I ever end throwing up hypothesis' in any formal discussions.

Yes. That is exactly my point. And that is why Inertial forces hurt so much.

So you agree to my argument that the inertial opposing force is the "by-product" of the acceleration caused by hitting with a hammer?

If I just leave the thing hanging from the string will the inertial force squash it on it's own?
If I park my car in the corner should I be worried that the inertial forces will push it in the woods?

When I ride my bike and twist the throttle the inertial forces push it into a wheelie (almost analogue to cornering with car).
Should I be scared the inertial forces might push it into a wheelie when I'm just trying to cruise around town?

No.

From my Dictionary, "reductio ad absurdum Latin. n. 1. a method of disproving a proposition by showing that its inevitable consequences would be absurd."

Which is exactly what I did. I assumed M-reasoning to be correct, then showed that its inevitable consequences are that NO FORCES ARE REAL, which is absurd (or, at least, pointless).

Does your dictionary also teach you how to use reductio ad absurdum correctly?

No.

The word "force" can be used in many ways, such as "the force of law", "force of personality", etc. I was NOT misusing this ambiguity to try to prove a point. Rather, I was trying to find which if those many types of "forces" could be classified as "real physical forces". The first two examples are NOT suitable, the rest are.

Well, let's call it spamming then. If you were not trying to prove a point, what where you trying to achieve? Gibberish?

I think the main problem here is that Modern Education doesn't do DEFINITIONS anymore. By contrast, open Book 1, Page 1, of Euclid's Elements and the first word is...

I agree it's a problem.

The double-negative in there suggests that you think Inertial forces might be real, even though in your ME-indoctrinated M-reasoning you said that they are "fictitious". I sense a confused young man.

Also if you read the first sentence of my post, it "suggests" (actually says) that I indeed consider inertial forces real. I sense an old man with an acute need of replacing his reading glasses.


I used the term "fictitious force" as it's the generally used term for inertial forces, not as any sort of reasoning. By the way, the only finnish translation equals "inertial force", so nothing to do with being real or not. Does this mean our education system is now better than yours?

The small boy in you knows that the fall is NOT the problem, rather it is the sudden stop at the bottom that hurts. This is a matter of common sense, which all small boys understand.

But the educated young man has been so thoroughly indoctrinated in the belief-system that whenever there is any mention of acceleration, then all common sense must be abandoned, and you must believe that any pain at the end of the fall is pure FICTION!

Again gish gallop, but for the sake of answering I think it's the force caused by hitting the ground (declerating me into a stop) that causes the pain.

And why the obsession with acceleration, and not position, velocity, electric-charge, etc.? (Rhetorical question, so think about it.)

(Or perhaps the confusion might be from Autumn-time hormonal urges... )

I think it's up to everyone to decide what approach they choose to work with. I usually use D'Alembert's principle as it works for me, and it's often approached with acceleration.

(Are you implying that you are too old for the hormons to effect or maybe stuff downstairs is not working anymore, so you have to relieve yourself to the FSAE forums?
I won't travel deeper into the path also known as ad hominem, you can keep it in your list of special latin-named repertoire.)

When you eventually decide what seems more reasonable to you (eg. Inertial forces are real, or NOT real, or on any other ME-related subject...), then please post your thoughts here on the Forum. I think we all enjoy well-reasoned discussions. But try to avoid the mistakes above...

For the time being I think I will continue the same way (inertial forces are real, and they're caused by accelerating an object). And I will also continue being openminded if I find something better or more suitable for me in the future.

I think the most important thing is to understand the flaws of the system you are using to simulate reality. The worriying thing for me is that there's a lot of people that don't understand this.

So for the University of 2015, we now want:
1. Change the name of fictititous forces to stop the discrimination of inertial forces
2. Better education about reasoning, argumenting and logical fallacies
3. ???