FAO : Louster

[tris-]

i understand your a bit of a maths pro (this is ofc open to anyone else who is a maths pro).

ive created a formula, literally out of no where, which will tell you the stopping distance differences on a dry road (dont take into account air friction etc) between your wheels locking and not locking.

it is as follows -

(Velocity/9.97)^2 = distance in meters.

for the scope of my work, i think its acceptable to say i came to it through trial, error and a bit of the 'try this for the hell of it' method (its only supposed to be simple maths). i came to 9.97 as i originally tried 10 (made sense for some reason) but didnt give enough of an accurate answer.

but i am interested to know why my formula works, because i simply have no idea. though it does work, and here is some proof -
difference is lockedwheel distance, less the non locked wheel distance

Velocity difference
1 0.01
10 1.01
20 4.02
30 9.05
40 16.10
50 25.15
60 36.21

so for an example we can use 10ms^2

(10/9.97)^2 = 1.006, round it up to give 1.01.

 

[Will]

Just to borrow Louster more, do you fancy helping Kirsty (my gf, you net her at my birthday last year) out with some quadratic graph stuff? Its probably pretty easy, but it isn't for me. PM me with some MSN or email details if thats cool.

 

[Clown]

Louster will you play me some more songs?

 

[Wonk]

can you repair my plane louster?

 

[Skyler]

Louster, I'm with NASA, can you help us with a space shuttle thing?

 

[tris-]

 

[ECA]

I am impressed your formula takes into account friction, brake exerted pressure and vehicle mass.

 

[TdC]

ROFL you've all just made an ill man laugh

 

[tris-]

I am impressed your formula takes into account friction, brake exerted pressure and vehicle mass.

im impressed too.
incase you misread, the formula only calculates the rate of increase in breaking distance between static and kinetic friction.

previous formula has already taken into account friction co-efficients and mass (and through simple maths, its found mass makes no difference to stopping distance )

and as stated previously, you are to ignore things like air friction and force exerted on break pads ,etc

 

[Paradroid]

You should publish it as Tris's Relative-Traction Coefficient, or something, and denote it with a penis symbol or a smilie face.

 

[old.user4556]

I used to be a constipated mathematician, but then i worked it out with a pencil.

 

[tris-]

You should publish it as Tris's Relative-Traction Coefficient, or something, and denote it with a penis symbol or a smilie face.

for the particular friction co efficients, i cant find anything on google which is anything like the formula above.


i may well have discovered something

 

[psyco]

I used to be a constipated mathematician, but then i worked it out with a pencil.

are you a dinosaur?

i may well have discovered something

or its wrong

 

[tris-]

are you a dinosaur?



or its wrong

its not wrong, look at the proof i posted in the first post

 

[Paradroid]

for the particular friction co efficients, i cant find anything on google which is anything like the formula above.

Yeah but aren't you looking at the difference between the friction and traction curves? The 9.97 is fairly close to gravity (9.8).

I would have thought that friction v's traction would be effected by the type of rubber and the design of the tread?

 

[tris-]

what im looking at is the difference in distances between locked and non locked wheels when a car is breaking.

i thought it was something to do with gravity aswell. then after some manipulation of my other formulas i got a number that wasnt far off natural log. no idea if its relevant though

 

[Chilly]

The process you followed was roughly regression. You knew the answers and wanted a formula to extrapolate unknowns from. You will probably find that if you take extreme examples, the answers become increasingly rubbish and at some point simply fail.

9.97 is very close to g (the acceleration due to gravity at sea level on Earth, on average) which is 9.98(etc etc). This is almost certainly a coincidence, though.

A simlistic view is to take the coefficient of friction between the tyres (in an average state - ie a normal temperature on a dry road with an average rubber compound) for the skid situation. And for the non skid you have to assume no skidding takes place and that your coefficient of friction is in effect the power of your brakes - this one will involve some innertia (hence calculus) calculations to prove. Also you need to assume that your braking power is infinitesimally small than the friction between tyre and road.

I could sit down and do it, but frankly I cba and im about to go out and get shitfaced.




/edit - natural log? You mean e? 2.71828183?


/edit 2 - having had a piss and thought about it: you obivously need to factor in the mass, velocity, gravity to get the answer. Friction due to air is roughly V^3 btw, its notoriously difficult to calculate and v^3 is very rough.

 

[Louster]

What the fuck.


I go out and away from the internet to actually do, you know, something for the first weekend ever and this happens?

Have you solved whatever it was yet? I haven't really read through and I have an assignment I need to do first is that okay.

Edit: oh wait it looks like this is, ahem, physics. Physics is not real math. It's all "approximation" this and "to second order" that. Goddamned.

 

[tris-]

What the fuck.


I go out and away from the internet to actually do, you know, something for the first weekend ever and this happens?

Have you solved whatever it was yet? I haven't really read through and I have an assignment I need to do first is that okay.

Edit: oh wait it looks like this is, ahem, physics. Physics is not real math. It's all "approximation" this and "to second order" that. Goddamned.

someone in DAoC OT has now formulated a lengthly and in depth reply which pretty much explains it all.

shouldnt you be happy you just got an FAO thread?

 

[Louster]

Yeah, it was more that it happened on the few days that I wasn't actually glued at my goddamned monitor. And in a subject that I don't really do. If you'd asked me about, say, the radius of convergence of power series I might have been able to help a little. What was the explanation anyhow?

 

[tris-]

understand its physics. its more the hows and whys of the maths that i was interested in. but here is an explanation either way -

https://forums.freddyshouse.com/showthread.php?t=214067&page=2

 

[TdC]

I go out and away from the internet to actually do, you know, something for the first weekend ever and this happens?

you know you must never leave usssss