> In a message dated 98-02-09 09:07:02 EST, richard.arnold@juno.com writes:
>
> << Am working on a project for school (an Evidence course). Scenario:
> Driver A shoots Driver B four times during an argument over whether B
> scratched A's MG with a key (semi-LBC content).
>
> Does anyone know:
>
> A. How fast a person is traveling in mph when they travel one mile in
> five, four, three, two, and one minutes? Actually, if someone could just
> tell me the formula for this, I'll figure it myself.
1 mile/five minutes = 12 mph
1 mile/four minutes = 15 mph
1 mile/three minutes = 20 mph
1 mile/two minutes = 30 mph
1 mile/one minute = 60 mph
>
> >>> Use each of the above for divisors and divide them into 60 for the mph.
>
> B. How long would it take an average adult person, at a normal pace, to
> cover six feet (in feet per second)? Same thing for the formula....
> Also, how does one convert feet per second into miles per hour?
>
Well, I've always considered a "normal" walking pace to be about
15 minutes per mile. Converting this to feet per second is
(5280/(15*60)), or 5.86 fps. Call it about six feet per second.
> C. How long would it take an average adult person, rushing, to cover
> six feet (in feet per second)?
>
Maybe a little less than a second.
> D. How fast does an average adult person move backwards (in feet per
> second)?
>
I don't think that anyone is coordinated enough to walk backwards as
well as they do forwards, so I would increase times by 50% or so.
> E. How long (in seconds or fractions thereof) it takes an average adult
> person to fire four shots from a pistol (assuming a double action
> revolver)?
Well, since you don't start timing until the first shot, it's free.
The remaining three shots would take about 2 additional seconds.
>
> The victim has four wounds that were all inflicted at approximately the
> same distance. The Defendant claims that he fired the shots with a
> slight pause between the first and second. He also claims that the
> victim was approximately six feet away and moving to attack the Defendant
> when the defendant was "forced to fire."
> >>> A parafin test can be conducted to check for gun powder residue to
> establish if the shots were fired at close range. Also, the angle of entry
> and exit wounds should be established to determine the body's position when
> struck by the bullets. My inclination is that a bullet of any caliber would
> most likely spin the victim around and/or stop the victim. I doubt that
> forward momentum would continue with four shots. I'm betting the first shot
> dropped the victim, and the others were fired from above while he was down!
> Serves him right for scratching the car!!!
Actually, almot no bullet, regardless of caliber, will "stop a victim
in his tracks", much less through him backwards. The impact felt by
the person being shot cannot be more than the recoil felt by the
shooter, and unless the pistol in question were a .454 Casull (which
is a single-action revolver anyway), the recoil forces involved
probably aren't that great. This is one case where we're a victim of
Hollywood stereotypes, where a shotgun blast can knock somebody
backwards ten feet. In reality, a victim will stagger, or just
crumple over without much histrionics.
> I have found that everyone is an expert when it comes to law enforcement
> and teaching. I just happen to have a degree in both. The above is my $.03
> worth and may not be credible. After all, I thought OJ was guilty!
I'm no law enforcement expert, but most of these problems fall under
simple physics, which I do have a background in. As for OJ, that's
why the possible verdicts from a jury are "guilty" and "not guilty",
rather than "guilty" and "innocent". Just because he was found "not
guilty" didn't mean he didn't do it... :)
Scott Gardner
Scott Gardner
gardner@lwcomm.com
www.lwcomm.com/~gardner
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