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OT Car crash Physics...



eliminate the bike rider's weight from the calculations.  His body had
virtually nothing to do with moving the Jag's fender.
  Front of Jag now eight feet back from original location? I don't believe
it.

Larry
Subject: Re: OT Car crash Physics...


> M1 is Jaguar XJS curb weight 4808lbs driver 165lbs ---> 2260kg
> M2 is Yamaha Motorcycle 360lbs + 125lbs ----->220kg
>
> Jaguar is stationary (waiting to turn left) and is struck by motorcycle
> headlong in the pass front fender.
>
> Front of car is displaced 8 feet (2.44m) back remains stationary,
wheelbase
> is 102" (2.59m)
>
> uK is a coefficient I found on the net.
>
> I want to calculate the inital velocity of the motorcycle.
>
> and no the motorcycle driver isn't doing so well....
>
>
>
> Jason Adams
----- Original Message -----
> From: "Jason" <jason@scirocco.org>
> To: "Jason Adams" <roclist@accessconsulting.ca>; "0sciroccolist"
> <scirocco-l@scirocco.org>
> Sent: Monday, October 28, 2002 1:42 PM
> Subject: Re: OT Car crash Physics...
>
>
> > At 03:57 PM 10/28/2002, Jason Adams wrote:
> > >With all the wealth of informed people on the list this shouldn't be
too
> > >difficult...
> > >
> > >If I know the weight of the cars, the skid distance, assume complete
> > >inelastic collision. how do I work it out...
> >
> > I'm confused here -- what are you trying to work out?
> >
> > >Vf^2 = Vo^2 + 2a(dS)
> > >
> > >is there something wrong with my assumption for 'a' ?
> >
> > Well, uK isn't a constant... the value you use is a "typical" value.
> Every
> > tire is different, as is every road surface.  And stopping distances on
a
> > car aren't that easy to compute -- you're dealing with 4 tires on an
> object
> > that has suspension and that does not have even weight distribution.
> >
> > "Typical" deceleration for a modern automobile is between 8.5 and 10
> > ms^-2.   Of course, some are far below, and a few are above.
> >
> > Using the 3 braking distance figures I have for the 16V from magazines
> (60,
> > 80mph from Road & Track, 70mph from Car & Driver), we can compute the
> > average a for the 16v's braking:
> >
> > 60mph   150 feet        7.87g
> > 70mph   196 feet        8.19g
> > 80mph   257 feet        8.16g
> >
> > The average of those 3 stops is 8.08g.  The 8V (158 feet from 60, 271
feet
> > from 80), averaged 7.61g.
> >
> > Of course, modern tires and brake pads improve those distances:  Two
years
> > ago I did 10 consecutive stops from 60 in my16V with Potenza RE71 tires
> and
> > Ferodo pads and used my G-Tech Pro to measure the distance.  I discarded
3
> > runs where the G-Tech did not provide an accurate reading, which left me
> > with 7 good runs.  I discarded the best and the worst runs, leaving 5
> > total.  The average of those 5 runs was 131.8 feet, which is an average
of
> > 8.95g.
> >
> > Jason
> >
> >
> >
> >
> >
> >
> >
>
>
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> Scirocco-l@scirocco.org
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>

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