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Article #1067

Re: Stopping and Starting!

#1067
From: Landon J Wood
Date: Fri, 23 Sep 1994 07:07
37 lines
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Obviously it all depends on how hard you press on the brake
and also how far away one starts braking.

In otherwords, is this an emergency stop or a gentle one.

More technically, determine the distance from the stop sign
you want to start accelerating ( a negative acceleration in this case)

If I remember my math, d = 1/2at^2 where d is distance , a is accel.
One could then solve for t (time).  Since you 2 unknowns here,
(a and t) one would have to use another relation, perhaps
2ad = v(f)^2 - v(i)^2 ;where v(i) is initial velocity and v(f) is
final velocity.  Solve this latter equation for a and then substitute
the resulting expression into the former equation.

Personally, I would get in the old wagon with a stop watch and
time a few stops.
If my math is screwed up I'm sure I'll hear about it :)
Smiles
Landon

>        I am in dire need of some (perhaps obscure) information. I need
>to know roughly how long it takes an automobile to stop at a stop sign
>from 40mph. I need to know the time of the stop as well as the dist. over
>which the negative acceleration took place.
>        The type of car I am concerned about is an average family car(a
>ford taurus, for example) and a sports car ( a mustang, 911 etc.).
>        Very general data about a generic car though would be fine.
>        Also I understand that the driver has a lot to do with the
>equation.  I'm just looking for a rough estimate and perhaps, if capable,
>any sort of arguments to support your data.
>        This is part of a much larger project, and I want a better
>estimate than I think I could give myself so if anyone can help,

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lwood@ednet1.osl.or.gov    |   Landwood@aol.com
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Date: Fri, 23 Sep 1994 00:07:56 -0700
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From: Landon J Wood <lwood@EDNET1.OSL.OR.GOV>
Subject: Re: Stopping and Starting!
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