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Re: [Phys-l] Falling Bullets--What is the question??



Rick,

long story, here is a short version:

the thread started with an observation about some people firing guns into the air at New years etc, and asked whether a "falling bullet" could kill someone.

A number of responses were "no, the terminal velocity is too low" and a number were "I know of such fatalities".

That was not very progressive, but then someone wrote a one-liner--all bullets are falling, which prompted the response that that was a smart ass comment and inappropriate, so the discussion then went on to the (non-netiquette) and whether the metacomment was inappropriate etc. (Someone did note that a bullet fired in a gun against a target does not fall. There were also some discussion of the semantics of "falling".

I guess I got annoyed mainly because I am interested in the original question, usually I just stop following when things go astray like this.

Cheers

Dick

Dick,

What's the back story on this? Interesting but vague!

Rick


Please pardon the brief intrusion of a philosopher with only a minor
in physics and an interest in philosophy of science education, who
has long lurked here appreciatively and silently.

It seems to me that the original interesting question* has been lost
in a muddle of quibbles about formulations of the problem and ad
hominen carping.

Here is a proposed reformulation of the original very interesting problem:

Consider a bullet fired from a (revolver/rifle--I will return to
this) with zero horizontal velocity from the surface of the earth
with no restriction at the muzzle and no interfering ceilings, etc.

If this bullet* , when it returns to the surface of the earth strikes
a human being (in the skull, in the shoulder--I will return to this)
what is the result?

The answer may depend on the initial muzzle velocity of the
revolver/rifle, the size of the bullet, and it may depend on where
in the body (see above) the missile strikes on its return. Relevant
answers should address these parameters.

MetaComments:

Of the twenty plus responses to this initial query, very few
addressed the basic question(s). Most focussed myopically on
defects in the formulation of the question, but did not contribute
toward a more precise formulation of the initial question to
contribute to better understanding nor contributed to answers.

If you think that a question is not well formulated, your best
professional response should also include either what you think is a
better formulation, or an explanation of why the question is
ill-conceived. Responses that criticize but don't contribue to
progress on these issues are less than optimally productive. I
believe that our profesional obligation is not only to criticize but
also to attempt to move the field forward.

One view of the field is that our sole obligation is to drag our feet
when someone seems to be moving toward falsehood; but another, more
optimistic, view is that we should try to contribute to moving
toward (approximate) truth.

I certainly don't have the expertise to answer your specific
questions, but I am convinced that if your community does not work
better collectively you neither will nor should have ANY leverage on
science education.


Richard Grandy
Philosophy & Cognitive Sciences
Rice University
Houston TX USA*

*Where many holidays lead to many firearms being fired skyward.
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Forum for Physics Educators
Phys-l@carnot.physics.buffalo.edu
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--
Richard A. Duschl
Dept Learning & Teaching
GSE-Rutgers University
10 Seminary Place
New Brunswick, NJ 08901-1183

rduschl@rci.rutgers.edu

tel: 732.932.7496 x-8111
fax: 732.932.7552
_______________________________________________
Forum for Physics Educators
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