Speed of Rubber

I did experiments like this 35 years ago, and knew it then. This is all old hat.

I have signed and dated documenation to prove it in one of my many boxes of files.

"I did experiments like this 35 years ago, and knew it then. This is all old hat.

I have signed and dated documenation to prove it in one of my many boxes of files."

Are you telling me you actually reinvented the wheel? Of course it's old hat.

The mechanical principle, which I invented and patented, reinvents the wheel.

Erich

I think that's great, so many people try to reinvent the wheel but get discouraged when people point out they're "reinventing the wheel". It must take a special fortitude to buckle down and actually reinvent the wheel.

plz wud u now stop fighting over it??

sorry to interrupt u but i cudn't hold myself n anyways it's really getting too long... at least stop that for the 'wheel's' or perhaps the 'rubber's' sake!!!!

I was not my intention to reinvent the wheel; the thought didn't even occur to me. All I needed was a key mechanical component to perform a certain function within an invention I was working on. I sifted through every known mechanical device and principle, tried every possible combination. I needed something new. I then relied on my conceptual ability and started to inventioneer. I mentally pushed it, 5-6 things going on at once, requiring absolute total concentration. The conceptual image emerged, and I had it! I immediately made up a mock model, tested by helping it, babying it through its infancy. I came to the conclusion that it was going to work. Drew up the specks and started with the patent search; then to the machine shop. Mashine shop tools are not designed to do this type of work. After a week of head scratching we all decided to at least try. After I received the patent, 2 weeks later I had the working model. For the first time I was able to see my creation perform a mechanical function which was new to the world. I attached it to a very low rpm power drill and watched it in slow motion. An absolutely amazing kinetic art object appeared for which I have no words to describe. My daughter is editing and transferring this onto discs. She will also set up a web site for your viewing. You know, it cannot be visualized, just by looking at the patent write up. I have over 15 new products designed with this mechanical principle, I'm sure there will be many more.

I have so many daily e-mails related to this thread, that I now commission it "Spam of Rubber."

Ing. Robert Forbus

Roger,

Amazing? It's just vector math. Is it amazing if I drop a bomb from an airplane and it doesn't fall straight down to the ground below the spot where I dropped it? Is it amazing if I fire a gun forward from the nose of a 273 mph airplane with a muzzle velocity of 400 fps (273 mph) and radar clocks the projectile at 546 mph? Or if I fire it from the tail, rearward, and it DOES fall almost straight to the ground below the spot I fired it over?

Please, send these to AMAZING STORIES magazine! (Yes, I know that AMAZING ceased publication last year!)

"Amazing? It's just vector math."

Yes, it's just vectors, still I find the fact that the rubber molecule is accelerated from 0 mph to 200 mph and back to 0 mph, ~50 times a second amazing. The molecule feels an acceleration of 200 mph / .02 sec or 89 m/s / .02 s = 4450 m/s² roughly 450 g's 50 times a second. Ouch.

I understand that different people find different things amazing, so if you don't, that's fine.

Small wonder that tires wear out! Created the re-thread industry.

in fact, the originator of this idea or this thread hasn't posted a single reply (sorry if i overlooked his name!) about what he thinks of all this (noticed?). now, isn't that amazing?

How about some logic? (and some very basic physics)

If the tire speed at time of contact with the road is zero, than the next part of the tire, even if molecular size, will also be zero isn't it? But there WILL be a difference in the TIME of contact between the two points of the tire, and the POINT of contact on the road . In another words, there will be a distance per time difference. Isn't that the definition of speed?

Wangito.

Let us simplify it even more. The tire rolls down the street. It hits a balloon filled with red paint. The balloon is squashed, splatters, and leaves a red splat on that area of the tread. The wheel continues to roll and transfers a red mark on the road on every revolution. If you are driving at 10 mph and increase the speed you will also see the splat on the road increase in speed. In other words you are measuring your speed in road splats.

Wangito,

That's along the lines of what I was thinking. How long is an instant? If we cannot reference time, we cannot calculate speed.

It'd be like taking a single, motionless frame from a movie of this car moving at a rate of 100 mph. Then you would have to ask yourself, "Is the car moving in the picture?"

Surely there were forces at work on the car and the tires as it was being driven, but to say it was moving while its motionless is an oxymoron.

Now, think about this. Let's say the car was being driven between the hours of 07:00:00 and 08:00:00 yesterday(any time in our past would work), at the given rate, 100 mph. At exactly 07:30:00, the car was only in one place at that specific time. It hasn't moved from that position until time has moved forward even the slightest amount, which I've found out to be a quanta - the fastest speed / the smallest length.

I've found no information as to the value of time an instance has. If it does have a value other than 0, I'd have to say the tire never completely stopped moving.

Try a peeled zero.

#95 and #97 please read #45. What do you think?

Gentlemen: Since I am a conceptual engineering inventor, I would like to introduce a new concept to you. Since our numerical system starts with 0-1-2-3-4-5 etc, we have no letter or symbol to represent the concept of nothing, because 0 is something. I suggest we take a 0- and backspace the - over the 0, or 0/ and backspace the / over the 0. I don't have that symbol on my computer, so just take a pencil and paper and try it. I think we need a nothing symbol for a clearer understanding in our scientific and engineering communications. What do you think?

Erich

"....Because 0 is something..."

No it isn't, its nothing, zero, zilch, sweet FA, infinitley less than something!!

Erich where exactly would you use your special symbol then?

And you nicked the 100th post as well....

John.

Erich,

You never studied, did you? There already is just such a concept in mathematics it is called "Approaching zero as a limit", and can be done from either the positive side or the negative side. I believe the symbology is something like this:

↑0⁺ and ↑0^-

or when talking about a variable, y, which is the limit of some function of a variable, x, as x approaches zero,

y = lim f(x), x→0

You idea of creating a new symbol is almost laughable. Firstly, how many word processors will let you back space over a zero and type a - or a / ? Oh, yeah, there is one, called a typewriter!

Secondly, there already are symbols that look like that. The symbol, Θ, is the Greek lether theta, and the symbol, Φ is the Greek letter, phi , which, when handwritten, appear very much as you proposed. Also, the synmbol, Ø, is used by some data processing systems and amateur radio operators to differentiate zero from the capital letter, O, because some people cannot see the difference between 0 and O, and some type fonts make them appear very similar.

Also, I don't quite understand your concept of zero as a something. As a quantity, zero IS nothing. Only as number is zero is something, it is a number representing the quantity of nothing!

Oh, yes, there is one case where zero can be something, some quantity, in absolute terms. That is in the case of relative scales which have negative and positive values, such as non-absolute temperature scales (Celsius, Fahrenheit) or relative pressure, positive and negative, as compared to ambient pressure (zero). But that is only because they are relative scales, and the numbers represent a relative difference from some standard. Well, come to think of it, zero still represents nothing, because the relative difference of zero on these scales IS nothing, that is, NO difference!

Forget the maths

Look at an 'action' snapshot of a passing racing car.

The top of the tyre will be vey blurred because it is moving forward very fast, as will be the rest of the car, but to a lesser degree because it is moving at half the speed.

The bottom of the tyre will be perfectly sharp, as will be the road surface, because neither are moving.

Does that help.

Horace,

I almost laughed at you when I read, "Forget the maths", but then I read the rest of your post. I said, almost, because your opening sounded like another bonehead analogy was about to be given as an illustration of scientific fact. I see warning signs when people say, forget about the math, or don't confuse me with the facts. Math is the language of science and scientific theories and laws are the building blocks of engineering and allow us to understand (at least to a limited extent) the world around us.

However, whilst others are jibber-jabbering on about, "an in instant in time", or "concept of nothing, because 0 is something", or other such hooey, you hit the nail on the head with your "thought" experiment.

Now, I wonder if anyone has tried this for real?

Although this may create more problems than it will solve, I thought I'd share some information I found. I've also taken the liberty to bold, italicize, and underline prudent information.

"To understand the magic formula, we need first to define its inputs, which include slip. Slip is an indirect measure of the fraction of the contact patch that is sticking. It is frequently asserted in the literature that a tyre with no slip at all cannot create forces. It has taken me a very long time to accept this assertion. Why can I steer a tin-toy car with metal tyres on a hard surface like Formica? If there is any slip in such tyres, it is microscopic, yet there are sufficient forces to brake and steer, even if just a little. I finally caved in when I realized that the forces are minute, also. If there is any friction between the tyre and the surface, there MUST be slip, as it is defined below. Though to a very small degree, the Formica and the tiny contact patches of the tin tyres actually twist and stretch each other. The only way to eliminate slip completely is to eliminate GRIP completely. Any grip, and you will have slip."

This was taken from this page: http://phors.locost7.info/phors21.htm

As to how accurate it really is, I don't have any idea. But I figured it was worth posting.

My assertion is that, if this guy is right, the tire never stopped moving, and yet wasn't going 100 mph at the point of contact either.

So what does everybody think now?

http://phors.locost7.info/contents.htm

Did you look at those formulas? Or understand them I mean. Most of it was over my head.

One thing I cannot do is prove any of the posts on this subject wrong, well maybe a couple. But if you look at all of my other comments, I have based them all on time. The definition of an "instant" / "instance". If there is no value of time to represent the length of an instant, we absolutely cannot calculate speed. And I may be wrong, time will tell. - sorry, just had to

As to being "nit-picky", as you mentioned, I'd have to say my thoughts on the question were very basic and straight-forward. He said the car was at 100 mph, ok, its being driven at 100 mph. He also mentioned the word instant. I took that word to it's face-value from answers.com. They said it was unperceptible. Until I get a value in relation to time for it, I can't say I'm wrong in my findings.

I've seen aurizon reposted the link to the magic formula. If that formula is accurate, then we're all wrong.

Well, The main thing is that with proper adhesion the tire patch that touches the road is at zero speed, relative to the road. That was the question.

Since the patch is finite and not a line contact or point contact there is a patch of the tire that is under differential stress. They call this stress 'tire squirm', and it gets less as the inflation pressure gets higher = smaller patch.

There is no question that the tire is at a constant velocity of 100 MPH, as is the vehicle.

There is no question that the top of the tire is going at 200 MPH relative to the road.

Ever hear of a 'cog railway'? The tires are metal gears and they engage a toothed section of track that goes up a hill. They also have a retainer so the wheel cannot diesengage. That toothed wheel is sure as hell going at zero velocity at the toothed track level. So let us say we have a cog railway going up/down hill at 100 MPH. Now do you see how the 'tire' must be at zero velocity?

http://en.wikipedia.org/wiki/Rack_railway

Velocity is distance in a unit time. You can measure how far it goes in 1 hour and if that is 100 miles = 100 miles per hours. We usually do not want to take long trips, so they usually use a tach generator that makes so many pulses per second as a wheel turns. The electronics have a built in look up table that tranlsates pulses per second into miles per hours. Earlier ones use electromagnetic drag forces on a shorted turn attached to a needle and rotate a magnet off the drive shaft, and calibrate it to miles per hours versus spring tension that rotates the needle in the speedometer.

you can measure how far a car moves in a microsecond and calculate the sped from that as long as your measurements are precise enough it will work fine.

I can't believe y'all are still trying to figure out the answer to this trick question.

Let me give you a hint: How fast is the engine turning in the car going 100 MPH?

OH! Yeah, that's right. Put the statics and physics books back and think about our nice little problem.

Is the engine turning 100 mph? It is connected to the tire in some manner.

You can't put a linear distance on a rotary movement unless it's attached to something moving linear.

The tire is attached to the car.

Your butt is in the seat of the car.

The car is moving 100 mph.

How fast is your butt moving? Zero? You had better get your butt moving back to school!

Put a grinding wheel in the chuck of a hand held drill. Hold the drill out the window, synchronize the speed of the drill with the pavement, touch the wheel to the pavement. How fast is the wheel going)? (hint: Look at the speedometer - Confused? Look at your butt, look at the drill in your hand, look at the tire on the car. They are all going 100 MPH!) Oh wait, glance out the window to see the tire at an exact moment touching the pavement while you're going 100 MPH to see how fast it is going when it does it. (At that exact moment look, one more time at your butt sitting in the seat going as fast as the tire and ask yourself why am I having to look at my butt........again?)

The top of the tire does indeed go 200 MPH. That's why the tops of tires always take half as long to get there. On a long trip, the top of the tires may be at your destination hours before the bottom drags it flat bottom in! It's a scientific fact! Yes just like the poster here who helped us see that the tops of tires in motion are always blurry in photographs. Unfortunately, at highway speeds of 70 to 75 MPH these tire tops may be going almost 150 MPH! Sad too because there is no one to steer them, not only that, they disobey stops signs like a New England politician!

I ask you, what further need of proof have do we need with all this dizzying intellect here pouring forth wisdom and science like a overflowing commode.

So, what, exactly is your point? You use a lot of words to say, what? Hard to tell how much of what you say is sarcasm and how much is your real answer.

Consider this. If a car in a harness, held off the ground, and you give it enough gas to get the speedometer to 100 mph. The tires are spinning right? The rubber molecules are moving right? Yet the car isn't moving. I think you'd agree that the velocity of the rubber molecule is NOT equal to the linear motion of the car in this case.

So what changes when the car is on the ground? The tires spin at EXACTLY the same speed as they did in the harness, and now the entire car moves forward at 100 mph. So what happened to the velocity due to the spinning tires, we don't count that anymore?

Also, consider this. Imagine a plane traveling at 300 miles per hour through the air and then landing at 300 miles per hour. While in the air, the tires on the plane do not spin, but when landing on the ground the tires on the plane spin very quickly. Are you suggesting that in both instances the rubber molecules of the planes tire are moving at the same speed? Afterall, the plane is moving 300 mph in both instances, is the rubber attached to the plane?

It seems to me, that, every reasonable fact presented in this discussion, is relative to the whole, however, since we are all individuals, we perceive things in a different way; sometimes our insights are different at relative times, depending on the comments which we receive on our statements, and this is also dependent on the space we are in at the time. Relatively, I would say that we are all correct, in our own relative way. However, there are those who are more correct, and individuals who are absolutely correct. What's Up Doc?

And "Some animals are more equal than others" - George Orwell, Animal Farm

Thanks all for your comments, it was very educational as well as entertaining.

Richard

Are you going to post the answer?

My Sincere apologies. For some strange reason, I can read but not post from 11 of the 12 PC's that I use each day. I suspect it has to do with the corporate firewall while I am at work.

I really don't have an answer to post. I just presented the two sides that my co-workers brought up with the hope that you gentlemen could add some light to the discussion. Most of you gave excellent thoughts and ideas. Everyone added to the thread. It was very enlightening and we got a lot of laughs also. I thank you all for that.

I would like to participate more actively in some of the threads, but that must wait till I can figure out how to get in here through more than one remote obscure door.

Cheers, Richard

So, if the car were to accelerate to 0.5C, what would the speed of the rubber at the top of the tyre be, assuming it could withstand the forces needed to hold it onto its rim at those rpms?

Tee hee...