remember the gut who got caught at 156mph ?

Man of Honour
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Originally posted by Sundance Kid
Wrong

Like Eyedot and Will also said -
An ABS car will stop shorter; we've had this debate many a time on here.




^ That post doesn't make any sense :confused:
It's obvious an F1 car will stop "a lot faster than the average road car"

The distance is still 100 Metres regardless how many seconds pass

But it does matter on the road. It affects your closing speed for a start.

Say someone pulls out at a junction 50 metres ahead of you, and you have to slam on the brakes. The car with better braking will stop sooner (and probably in less distance) than the other car. Because of the time factor, the other car actually has more time to pull away out of the danger zone, the time factor is reduced. (assuming the same speed). Your assumption that all stopping distances are the same is what has caused confustion.

It's simple newtonian physics. That's why distance and time have separate values. There's also the fact that reaction time is pretty constant, so the only place to make savings is with cars that stop faster (or in a shorter distance, or a combination of both). The decelaration of some cars under braking is much higher than others.

By bringing F1 cars into the equation, you have confused the issue. Look at road cars, and tell me that they all stop in the same distance and time, they blatantly don't. Some will stop in similar distances but in shorter time, others in shorter distances, and so on and so on.

If this wasn't the case, we'd all still be on wire operated drum brakes.
 
Soldato
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Originally posted by EyeDot
For that, i think he needed a harsher punishment, as i HATE uninsured drivers..

Me too

I think all drivers (caught) without insurance should be banned from driving for life and forced to repay the damages regardless of how many years it takes them.

I see too many ‘kids’ driving cars that there is no way they could get insured on :mad:
 
Associate
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Originally posted by EyeDot
We have to rememebr here tho, its not a clean cut speeding charge

he was banned, and uninsured as well.

For that, i think he needed a harsher punishment, as i HATE uninsured drivers..

I have to agree that if it was just speeding alone, a ban and a large fine would be sufficient.

As he was already banned and uninsured though, he needed to be taught a lesson.

The media will hype up the 155 mph thing though and hardly mention the insurance/ban aspect, which I think is more important than the speeding.

(Though 120 in a 40 zone is plain stupid).
 
Don
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don't know what it proves but as we are getting all scientific

cs.gif

Perhaps you learned in a drivers education course of this mathematical relationship between initial speed and stopping distance. But did you know that the relationship is based upon the physics of work and energy? Prior to braking each car has kinetic energy (energy due to motion). The amount of kinetic energy is dependent upon the mass and the speed of the car according to the equation

KE = 0/5*mass*(speed)2
The blue car has the most kinetic energy since it has the greatest speed. This is portrayed in the work-energy bar charts above by the height of the KE bar for each car.

Once the brakes are applied, the force of friction acts upon the car. The work done by friction on the skidding car is proportional to stopping distance according to the equation

Work = Force * displacement * cosine(Theta)
where the displacement of the car is simply the distance the car skids to a stop and Theta is the angle between the force and the displacement vectors. In this case, Theta is 180 degrees since the force of friction and the displacement of the car are in opposite directions.

The work-energy theorem can be used to relate the work done by friction on the car to the initial kinetic energy of the car. The work-energy theorem is stated as an equation in the form of

KEi + PEi + Wext = KEf + PEf
Since the potential energy of the car is the same in the initial state (before braking) as the final state (after stopping), each term can be cancelled from the above equation. And since the car is finally stopped, the KEf term in the equation is zero. Thus, the equation becomes

0.5*m*v2 + F*d*cos(180) = 0.
This equation can be rearranged so that it takes the form of

0.5*m*v2 = -F*d*cos(180)
and since the cosine(180) is -1, the equation can be re-written as

0.5*m*v2 = F*d.
The above equation shows that the stopping distance (d) is proportional to the square of the speed (v2). And that's exactly what the driver's education course taught you. But now you know: it's PHYSICS!


--------------------------------------------------------------------------------

:p
 
Soldato
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Yup I understand

My point about bringing the F1 car into it was to compare moss’s Micra stopping from 70 to an Impreza stopping from 150.
I only know the average stopping distance for cars (i.e. Not specific models) and used the F1 car as the ultimate benchmark that no road car could beat. Therefore proving that a Micra (or average road car) travelling at 70Mph could stop shorter (distance) than an F1 car travelling at 150mph.

Time has no meaning for the above example, which is why I didn’t mention it

:: EDIT ::

LOL Will Gill, nice graph but all this is doing my head in - grrr :\
 
Soldato
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Originally posted by Sundance Kid
Sticking with the braking thing

It's takes an average road car 96 metres to stop from 70MPH
It's takes an F1 car approx 100 Metres to stop from 150mph

I think your Micra would stand a good chance of stopping before a Scooby at those speeds :)

And what is an average road car?
Mondeo, Escort, Focus, etc...none of which are designed for high speeds.
 
Soldato
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I despise uninsured drivers, to drive without insurance is purely selfish so I'm glad he got what he did.

156mph is a bit excessive to me. I dont see the need for it.

As he was already banned and uninsured I can see why they sent him to prison, what were they going to do otherwise??? Ban him again??? It obviously had no effect the first time round so what other choice did they have.
 
Soldato
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Originally posted by G-Man
And what is an average road car?
Mondeo, Escort, Focus, etc...none of which are designed for high speeds.

What does high speeds have to do with it ??
 
Man of Honour
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But in your example, you are taking two different bases and ignoring the other factors.

A better comparison would have been the average car vs the F1 car at the same speed, as it shows the difference in decelaration by only really altering one variable, rather than two (or even three, as the distance changes too)

If I can find some figures for common road cars, I'll have a go at doing some calculations based on them for a better idea.

-Dolph
 
Man of Honour
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Originally posted by Sundance Kid
What does high speeds have to do with it ??

The total amount of negative acceleration achieved by braking depends on the car. Some cars generate much more braking force than others. (For instance, one with large grippy tyres and huge vented disc brakes can get a much higher stopping force than a supermini with drums and the back and tiny skinny tyres.)

Hence from the same speed, a car with more stopping power will stop faster, and from higher speeds, the same applys.

-Dolph
 
Caporegime
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Originally posted by EyeDot
We have to rememebr here tho, its not a clean cut speeding charge

he was banned, and uninsured as well.

For that, i think he needed a harsher punishment, as i HATE uninsured drivers..


So, best we rememebr that, had he hit someone, they would have been up the duff and forced to seek payment from the MiB, something our premiums contribute to!

yeah were not condoning the driving whilst un-insured and banned

were complaining about the attitude of the article that stated that he was basically the scum of the earth for the speed he was doing.
 
Soldato
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Originally posted by Dolph
But in your example, you are taking two different bases and ignoring the other factors.

A better comparison would have been the average car vs the F1 car at the same speed, as it shows the difference in decelaration by only really altering one variable, rather than two (or even three, as the distance changes too)

Think you've missed the point of my example.
Not comparing stopping times and it's obvious most cars will stop shorter from the same speed as the Micra.

Just what would stop shorter (distance) :

A Micra travelling at 70mph
An Impreza travelling at 150mph
 
Soldato
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Originally posted by Dolph
The total amount of negative acceleration achieved by braking depends on the car. Some cars generate much more braking force than others. (For instance, one with large grippy tyres and huge vented disc brakes can get a much higher stopping force than a supermini with drums and the back and tiny skinny tyres.)

Hence from the same speed, a car with more stopping power will stop faster, and from higher speeds, the same applys.

-Dolph

Originally posted by G-Man
Well logically a car designed for high speeds will also be designed to be able to safely and quickly stop from said high speeds.


grrrrrr !!!
I know !!!!!

That wasn't the point of my example. Obvious a car designed for high speeds will stop safely and quickly from a high speed.

But it won't stop in a shorter distance when compared to a car @ 70 to another car @ 150, regardless of what braking systems or tyres they are fitted with !!!!


Never mind :)
 
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