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[BazaJT]

Don't know if anyone else saw/read this,but a short while ago in a car magazine i read an article about the braking rate of a car is not a linear progression but that most of the braking effort comes when near a standstill.To show this they took a police Omega[with police driver]to a test track,took the car up to 70m.p.h. and did an emergency stop.Measurement and marking were done from the pre-determined braking point to where it came to a stop.The car was then set off again and taken up to 100m.p.h.and at the same braking spot another emergency stop performed.At the time the Omega passed the marker where it had stopped on the first test it was still travelling at 70m.p.h.!!!

[tigers_gonads]

Got told something simliar by a advanced driving instructor while on a speeding course many moons ago.

2 cars travelling down the same road.
Car 1 is travelling at 70 mph
Car 2 is travelling at 100 mph.
Tanker jack knifes infront of them both.

The car that was travelling at 70 mph stops with a inch to spare.
The car that was travelling at 100 mph hits the tanker at 70 mph 

Got to admit, that little fact made my arse twitch a little.

[Abiton]

KE=½mv² 

innit. 

[cem_devecioglu]

KE=½mv² 

innit. 

yep.. 
 
can be translated as the energy of a moving object is proportional to its velocity squared..  as the brakes and tyres have to compansate this energy this distance gets much longer.. and as speed increases friction coefficient decreases ..

[hercules]

gotta admit it...for the sake of doing 30mph more your gonna slam into something at 70mph 
im glad as im getting older im realising whats the rush

[Kevin Wood]

If you want to go fast, just get a lighter car.

[hercules]

If you want to go fast, just get a lighter car.

mine doesnt weigh much 

[Mr Skrunts]

If you want to go fast, just get a lighter car.

Or fit more capable brakes.   

[geoffr70]

If you want to go fast, just get a lighter car.

Or fit more capable brakes.   

Or ignore speed limits and close your eyes!

[Nick W]

Don't forget that braking distances also increase if you're travelling downhill.

[omega3000]

If you want to go fast, just get a lighter car.

Mine is lighter each day with the rust falling off it 

gotta admit it...for the sake of doing 30mph more your gonna slam into something at 70mph 
im glad as im getting older im realising whats the rush

+1 

[Abiton]

If you want to go fast, just get a lighter car.

Well yes, that helps, but it doesn't make the square function go away.

If you want to go fast, just get a lighter car.

Or fit more capable brakes.   

Fitting more capable brakes probably isn't relevant.  The asphalt to tyre interface is likely the limiting factor for a single stop. With servo-assistance and ABS, a good stomp on the pedal will safely bring you to limiting tyre adhesion and keep you there until you stop (one way or another).

Some interesting discussion of tyres and grip here: http://www.f1technical.net/forum/viewtopic.php?f=6&t=12762
Follow the very first link in there to a thread with a post by Ciro, then follow all his stuff.  Should fill a lazy Sunday. 
 

[cem_devecioglu]

If you want to go fast, just get a lighter car.

Well yes, that helps, but it doesn't make the square function go away.

If you want to go fast, just get a lighter car.

Or fit more capable brakes.   

Fitting more capable brakes probably isn't relevant.  The asphalt to tyre interface is likely the limiting factor for a single stop. With servo-assistance and ABS, a good stomp on the pedal will safely bring you to limiting tyre adhesion and keep you there until you stop (one way or another).

Some interesting discussion of tyres and grip here: http://www.f1technical.net/forum/viewtopic.php?f=6&t=12762
Follow the very first link in there to a thread with a post by Ciro, then follow all his stuff.  Should fill a lazy Sunday. 

I followed all the links Abiton.. thanks for them..
 
Ciro seems to know the job and models.. However, with nowadays sciences, things are so complex that not everything can be easily modelled and calculated.. Instead , many tests are done with respect to changing factors ,results are measured and the mathematical models developed later.. And simplified for practical reasons for daily usage..  

[m.ian]

does thinking time also have a part to play when travelling at those speeds?

[cem_devecioglu]

does thinking time also have a part to play when travelling at those speeds?

yes    if your reactions are a bit slow you will hit with the same speed