physics question about braking distances...
07-14-2005, 10:38 AM
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physics question about braking distances...
I am wondering if you were to graph a curve of speed of the car vs braking distance required to stop, would the curve be linear or exponential?
07-14-2005, 10:59 AM
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assuming that everything else is the same - think it's not linear (edited)
if the amount of time that it takes to react to hit the brakes is the same, the amount of distance travelled at higher velocity would be greater, so that would add to the overall distance needed to do a stop (hence, not linear). If you cut out the distance travelled during the reaction time, then I think it's linear.
07-14-2005, 11:40 AM
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im pretty sure it wouldn't be linear. . . . .
the reason being you can apply different amounts of pressure to the brakes which will affect the stopping distance. for example, start of by slowly depressing the brake followed by slamming the brake to the floor. this will not produce a linear braking force vs. distance graph.
07-14-2005, 11:42 AM
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Definitely not linear, but just as definitely not exponential...
In an ideal world where there's no brake fade, the brake force would stay constant, so that F=ma=m(dv/dt). Integrate that and you'd get v=(F/m)*t, or a straight line. However, brake fade skews the brake force to less than the initial value over time. As well, if you start taking into account that the faster you go, the more drag there is such that the effective slowing force is higest when you first apply your brakes, it would definitely not be a straight line, but some form of decaying line that I'm too lazy to try to derive :P
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07-14-2005, 04:26 PM
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I was watching a show on the autobahn and..
They were talking about how speeds of like 180mph are very dangerous. they said that if a car was going that fast it would take half a mile to slowdown.
I'm sorry, but if a car can hit 180mph, its obviously a well built car and most likely has good brakes. i find it hard to believe that when you go 180mph it will take about 2500ft to stop.
And it just got me thinking about 60-0 is about 120ft, what would 180-0 be. and I just cant believe its 2500ft
I'm sorry, but if a car can hit 180mph, its obviously a well built car and most likely has good brakes. i find it hard to believe that when you go 180mph it will take about 2500ft to stop.
And it just got me thinking about 60-0 is about 120ft, what would 180-0 be. and I just cant believe its 2500ft