# Physics of Daytona

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Originally Posted By: MolaKule
Now that we have all the math completed, one can use a Us of 0.9 and calculate the real world safe MAXIMUM speed in m/s or mph. Multiply m/s by 2.24 to get the mph.
Since the actual Us = 0.93 as tested, we will use 0.9 for an extra margin of safety. g = 9.8 m/s, r = 316 m theta = 31 degrees. Using Us = v^2.cos(theta)/g.r from above. Us.g.r = v^2.cos(theta), Us.g.r/cos(theta) = v^2 v = sqrt(Us.g.r/cos(theta)) v = sqrt(0.9.9.8.316/cos(31)) v = sqrt(2787/cos(31)) = sqrt(2787/0.857) = 57 m/s v = 127.7 mph.

Originally Posted By: MolaKule
Since the actual Us = 0.93 as tested, we will use 0.9 for an extra margin of safety.
How do they test that for track use? Do they measure the deceleration directly? I know the coefficient of friction can be measured fairly easily for a "normal" tire surface on a "normal" road without any electronics, of course. Heck, there are enough estimates that are good enough for most purposes, including court.

I'm interested how a Us of 0.93 can provide a higher safe speed than a Us of 1 does in the original calculation.

Originally Posted By: Shannow
I'm interested how a Us of 0.93 can provide a higher safe speed than a Us of 1 does in the original calculation.
Lets keep this thread technical. Deceleration is not a real thing. Acceleration is either positive or negative in direction, but both directions are acceleration.

Originally Posted By: Shannow
I'm interested how a Us of 0.93 can provide a higher safe speed than a Us of 1 does in the original calculation.
Lets keep this thread technical. Deceleration is not a real thing. Acceleration is either positive or negative in direction, but both directions are acceleration.
I am...the original premise was that U=1, and could therefore be ignored, which I disagreed with...as the calculations, in ignoring U, were essentially U=0, or the free body on the track without radial effects from tyre friction. This latest calculation with U=0.93 demonstrates that what I stated first WAS the case, in providing a higher corner speed "at the limit of adhesion" than the original calculation...which was my tongue in cheek "how can a less grippy tyre provide greater cornering speed" ? Now where on Earth did you get that I was talking about deceleration from ???

Ever ride a bike on that bassssttttardddd?

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You should try it sometime. Like wrestling a gator in the swamps of the Keys, except with road rash. Physics don't really enter into the "equation".

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Originally Posted By: Concours14
Ever ride a bike on that bassssttttardddd?
No, but I have driven my Corvette and Camaro on it. The lateral G's on the banking aren't much of a challenge up to the 168mph that I've done there.

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