Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > sci.physics > #544173 > unrolled thread

MythBusters: Bringing on the physics bullet drop

Back to article view | Back to sci.physics

Contents

  MythBusters: Bringing on the physics bullet drop Sam Wormley <swormley1@gmail.com> - 2016-01-09 20:54 -0600
    Re: MythBusters: Bringing on the physics bullet drop jimp@specsol.spam.sux.com - 2016-01-10 03:09 +0000
      Re: MythBusters: Bringing on the physics bullet drop pnalsing@gmail.com - 2016-01-09 21:25 -0800
        Re: MythBusters: Bringing on the physics bullet drop jimp@specsol.spam.sux.com - 2016-01-10 06:27 +0000
          Re: MythBusters: Bringing on the physics bullet drop pnalsing@gmail.com - 2016-01-10 10:00 -0800
            Re: MythBusters: Bringing on the physics bullet drop jimp@specsol.spam.sux.com - 2016-01-10 20:55 +0000
              Re: MythBusters: Bringing on the physics bullet drop pnalsing@gmail.com - 2016-01-10 13:40 -0800
                Re: MythBusters: Bringing on the physics bullet drop jimp@specsol.spam.sux.com - 2016-01-10 22:21 +0000
                  Re: MythBusters: Bringing on the physics bullet drop pnalsing@gmail.com - 2016-01-10 15:56 -0800
                    Re: MythBusters: Bringing on the physics bullet drop jimp@specsol.spam.sux.com - 2016-01-11 00:20 +0000
                      Re: MythBusters: Bringing on the physics bullet drop pnalsing@gmail.com - 2016-01-10 16:58 -0800
                        Re: MythBusters: Bringing on the physics bullet drop jimp@specsol.spam.sux.com - 2016-01-11 01:16 +0000
        Re: MythBusters: Bringing on the physics bullet drop Poutnik <poutnik4nntp@gmail.com> - 2016-01-10 10:12 +0100
          Re: MythBusters: Bringing on the physics bullet drop john <johnsefton288@gmail.com> - 2016-01-10 04:38 -0800
      Re: MythBusters: Bringing on the physics bullet drop R Kym Horsell <kym@kymhorsell.com> - 2016-01-10 22:29 +0000
        Re: MythBusters: Bringing on the physics bullet drop jimp@specsol.spam.sux.com - 2016-01-10 23:13 +0000
    Re: MythBusters: Bringing on the physics bullet drop Double-A <double-a3@hush.com> - 2016-01-10 10:27 -0800
      Re: MythBusters: Bringing on the physics bullet drop R Kym Horsell <kym@kymhorsell.com> - 2016-01-11 01:23 +0000
        Re: MythBusters: Bringing on the physics bullet drop jimp@specsol.spam.sux.com - 2016-01-11 03:16 +0000
          Re: MythBusters: Bringing on the physics bullet drop john <johnsefton288@gmail.com> - 2016-01-10 20:08 -0800

#544173 — MythBusters: Bringing on the physics bullet drop

MythBusters: Bringing on the physics bullet drop
> http://www.wired.com/2009/10/mythbusters-bringing-on-the-physics-bullet-drop/


> If you didn’t catch the latest MythBusters (yeah! new episodes), they
> did something straight from the physics textbooks. Just about every
> text has this example of shooting a bullet horizontally and dropping
> a bullet from the same height. The idea is that they should hit the
> ground at the same time. No one but the MythBusters could actually
> show this demo with a real gun.
>
> The Physics
>
> I am going to do some calculations, but I want to first write about
> the physics that accompanies this idea (and you can actually do it
> your self without the gun). What physics principle does this demo
> show? Well, it shows two things. First, it shows that the horizontal
> and vertical motion in projectile motion are independent. That is,
> what happens in the y-direction, stays in the y-direction. Really,
> you can treat projectile motion as two separate problems that just
> happen to take the same amount of time. The second thing it shows is
> that the velocity in one direction does not effect the velocity in
> the other direction (which really is the same as the first thing).
> Let me draw two diagrams, one for a dropped ball and one for ball
> shot horizontally.


-- 

sci.physics is an unmoderated newsgroup dedicated
to the discussion of physics, news from the physics
community, and physics-related social issues.

[toc] | [next] | [standalone]

#544179

Sam Wormley <swormley1@gmail.com> wrote:
> MythBusters: Bringing on the physics bullet drop
>> http://www.wired.com/2009/10/mythbusters-bringing-on-the-physics-bullet-drop/
> 
> 
>> If you didn?t catch the latest MythBusters (yeah! new episodes), they
>> did something straight from the physics textbooks. Just about every
>> text has this example of shooting a bullet horizontally and dropping
>> a bullet from the same height. The idea is that they should hit the
>> ground at the same time. No one but the MythBusters could actually
>> show this demo with a real gun.
>>
>> The Physics
>>
>> I am going to do some calculations, but I want to first write about
>> the physics that accompanies this idea (and you can actually do it
>> your self without the gun). What physics principle does this demo
>> show? Well, it shows two things. First, it shows that the horizontal
>> and vertical motion in projectile motion are independent. That is,
>> what happens in the y-direction, stays in the y-direction. Really,
>> you can treat projectile motion as two separate problems that just
>> happen to take the same amount of time. The second thing it shows is
>> that the velocity in one direction does not effect the velocity in
>> the other direction (which really is the same as the first thing).
>> Let me draw two diagrams, one for a dropped ball and one for ball
>> shot horizontally.
 
Except real bullets in air have some lift depending on the bullet shape,
cut and paste spamming shit head.

 

-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#544192

On Saturday, January 9, 2016 at 7:31:07 PM UTC-8, ji...@specsol.spam.sux.com wrote:

> Except real bullets in air have some lift depending on the bullet shape,
> cut and paste spamming shit head.

Well, why don't you just cut and paste a few links that support this statement. I couldn't find a single one myself, perhaps you will have better results.

In the meantime, here are a few that refute your statement.

http://guerillatics.com/?p=137

"This post is for all you gun enthusiasts that think you know all there is to know about guns. It is especially for those of you who think that a bullet rises as it comes out of the barrel. It doesn't! I dont care how long you've been hunting or shooting or what. The freakin bullet doesn't rise as it comes out of the barrel.  As soon as it exits the barrel the bullet begins to fall due to gravity. It never rises past the axis of the barrel."http://www.chuckhawks.com/bullet_trajectory.htm

http://www.chuckhawks.com/bullet_trajectory.htm

"... bullet never rises above the axis of the barrel."

http://www.sniperforums.com/forum/cartridges-calibers/2746-myth-rising-bullet.html

"... any projectile, be it free upon exit, is always falling."

http://forum.pafoa.org/showthread.php?t=37393

"A bullet fired parallel to the ground begins to fall the instant it exits from the muzzle."

Don't bother bring up the Magnus Effect, a little Google study shows that this only makes bullets wander left or right, depending on the direction of the rifling in the barrel.

Your move.

[toc] | [prev] | [next] | [standalone]

#544198

pnalsing@gmail.com wrote:
> On Saturday, January 9, 2016 at 7:31:07 PM UTC-8, ji...@specsol.spam.sux.com wrote:
> 
>> Except real bullets in air have some lift depending on the bullet shape,
>> cut and paste spamming shit head.
> 
> Well, why don't you just cut and paste a few links that support this statement. I couldn't find a single one myself, perhaps you will have better results.
> 
> In the meantime, here are a few that refute your statement.
> 
> http://guerillatics.com/?p=137
> 
> "This post is for all you gun enthusiasts that think you know all there is to know about guns. It is especially for those of you who think that a bullet rises as it comes out of the barrel. It doesn't! I dont care how long you've been hunting or shooting or what. The freakin bullet doesn't rise as it comes out of the barrel.  As soon as it exits the barrel the bullet begins to fall due to gravity. It never rises past the axis of the barrel."http://www.chuckhawks.com/bullet_trajectory.htm
> 
> http://www.chuckhawks.com/bullet_trajectory.htm
> 
> "... bullet never rises above the axis of the barrel."
> 
> http://www.sniperforums.com/forum/cartridges-calibers/2746-myth-rising-bullet.html
> 
> "... any projectile, be it free upon exit, is always falling."
> 
> http://forum.pafoa.org/showthread.php?t=37393
> 
> "A bullet fired parallel to the ground begins to fall the instant it exits from the muzzle."
> 
> Don't bother bring up the Magnus Effect, a little Google study shows that this only makes bullets wander left or right, depending on the direction of the rifling in the barrel.
> 
> Your move.

The effects are tiny but real.

A bullet fired horizontally with respect to the Earth will maintain it's
attitude throughout the flight. As it is dropping, it has a positive
angle of attack and hence a tiny bit of lift that will depend on the
exact shape of the bullet.

Some may argue that there is no lift because a bullet is symmetrical,
but symmetrical shapes, such as aerobatic aircraft wings and balsa
wood gliders with flat wings have lift due to the angle of attack.

Also, since the fired bullet is always horizontal, the vertical drag
will equal that of a dropped bullet only if the bullet is dropped
oriented exactly horizontally. A bullet dropped nose first will have
less drag than a horizontal bullet.



-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#544260

Does this mean you cannot produce any links at all that support your claim? 

[toc] | [prev] | [next] | [standalone]

#544304

pnalsing@gmail.com wrote:
> Does this mean you cannot produce any links at all that support your claim? 

Does this mean you cannot produce any links at all that refute my claims?

I'll throw you a bone; high speed photography shows bullets impacting
targets at the same attitude as they were fired.


-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#544310

On Sunday, January 10, 2016 at 1:01:05 PM UTC-8, ji...@specsol.spam.sux.com wrote:
> pnal...@gmail.com wrote:

> > Does this mean you cannot produce any links at all that support your claim? 
> 
> Does this mean you cannot produce any links at all that refute my claims?

I produced several links that refuted your claim, that claim being that bullets have lift... and having lift implies that they rise. They do not rise.

> I'll throw you a bone; high speed photography shows bullets impacting
> targets at the same attitude as they were fired.

Agreed. So what? What does this have to do with lift?

Again, You have claimed that bullets fired from a rifle have lift. This may be true, but I cannot find any evidence of this searching the internet other than a few sportsmen that make the same claim, but without presenting any evidence whatsoever. If rifle bullets DO have lift, I would surely like to see the evidence, and therefore I asked to YOU, as the claimant, to put some money where your mouth is and provide that evidence in the form of a scientific explanation, but apparently you are not able to come up with any links either. I'm not insisting that you are wrong, but I am suggesting that you should be able to prove that you are correct.

\Paul A

[toc] | [prev] | [next] | [standalone]

#544317

pnalsing@gmail.com wrote:
> On Sunday, January 10, 2016 at 1:01:05 PM UTC-8, ji...@specsol.spam.sux.com wrote:
>> pnal...@gmail.com wrote:
> 
>> > Does this mean you cannot produce any links at all that support your claim? 
>> 
>> Does this mean you cannot produce any links at all that refute my claims?
> 
> I produced several links that refuted your claim, that claim being that bullets have lift... and having lift implies that they rise. They do not rise.
> 

Read your links closely.

I never claimed bullets rise.

A glider in calm air has lots of lift but it does not rise when in eqilibrium.

What I claimed was that the vertical rate of descent of a fired bullet
is less than that of a dropped bullet in air.


>> I'll throw you a bone; high speed photography shows bullets impacting
>> targets at the same attitude as they were fired.
> 
> Agreed. So what? What does this have to do with lift?

It shows the angle of attack.

FYI angle of attack is the angle between the chord line and the vector
representing the relative motion between the body and the air through
which it is moving.

> Again, You have claimed that bullets fired from a rifle have lift. This may be true, but I cannot find any evidence of this searching the internet other than a few sportsmen that make the same claim, but without presenting any evidence whatsoever. If rifle bullets DO have lift, I would surely like to see the evidence, and therefore I asked to YOU, as the claimant, to put some money where your mouth is and provide that evidence in the form of a scientific explanation, but apparently you are not able to come up with any links either. I'm not insisting that you are wrong, but I am suggesting that you should be able to prove that you are correct.
> 
> \Paul A
 
It is all basic and obvious physics.

It is basic physics that an object moving through air with a positive
angle of attack has lift. Perhaps not a lot, but some and certainly
not enough to cause the bullet to rise. There are lots of links that
discuss the concept of lift and angle of attack.

It is basic physics that the vertical drag of a bullet will depend on
the orientation. This should be blazingly obvious.

For a falling bullet to have the same vertical drag as a fired bullet,
it would have to be dropped with the same attitude as the fired bullet
and that attitude would have to be maintained throughout the fall through
some external force.


-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#544346

On Sunday, January 10, 2016 at 2:31:05 PM UTC-8, ji...@specsol.spam.sux.com wrote:
> pnal...@gmail.com wrote:
> > On Sunday, January 10, 2016 at 1:01:05 PM UTC-8, ji...@specsol.spam.sux.com wrote:
> >> pnal...@gmail.com wrote:
> > 
> >> > Does this mean you cannot produce any links at all that support your claim? 
> >> 
> >> Does this mean you cannot produce any links at all that refute my claims?
> > 
> > I produced several links that refuted your claim, that claim being that bullets have lift... and having lift implies that they rise. They do not rise.
> > 
> 
> Read your links closely.
> 
> I never claimed bullets rise... What I claimed was that the vertical rate of descent of a fired bullet is less than that of a dropped bullet in air.

Well then, what you claimed agrees completely with what was said in the link that Sam posted...

"There you have it. The y-component of air resistance for the fired bullet still depends on the fired speed of the bullet (since it is proportional to v2). A fired bullet (with air resistance) does not hit the ground at the same time as a dropped bullet."

... so why bother with the snarky remark in the first place?

In my opinion, I think using the word "lift" for this is a poor choice of words, I clearly thought you were talking about something very different.

[toc] | [prev] | [next] | [standalone]

#544354

pnalsing@gmail.com wrote:
> On Sunday, January 10, 2016 at 2:31:05 PM UTC-8, ji...@specsol.spam.sux.com wrote:
>> pnal...@gmail.com wrote:
>> > On Sunday, January 10, 2016 at 1:01:05 PM UTC-8, ji...@specsol.spam.sux.com wrote:
>> >> pnal...@gmail.com wrote:
>> > 
>> >> > Does this mean you cannot produce any links at all that support your claim? 
>> >> 
>> >> Does this mean you cannot produce any links at all that refute my claims?
>> > 
>> > I produced several links that refuted your claim, that claim being that bullets have lift... and having lift implies that they rise. They do not rise.
>> > 
>> 
>> Read your links closely.
>> 
>> I never claimed bullets rise... What I claimed was that the vertical rate of descent of a fired bullet is less than that of a dropped bullet in air.
> 
> Well then, what you claimed agrees completely with what was said in the link that Sam posted...
> 

No, it does not.

> "There you have it. The y-component of air resistance for the fired bullet still depends on the fired speed of the bullet (since it is proportional to v2). A fired bullet (with air resistance) does not hit the ground at the same time as a dropped bullet."
> 
> ... so why bother with the snarky remark in the first place?

1. The poster is a cut and paste spamming ass hat.

2. The cut and paste article is simplistic.

> In my opinion, I think using the word "lift" for this is a poor choice of words, I clearly thought you were talking about something very different.

I said lift and I meant lift and both you and the article completely
ignored my remarks about drag and orientation.


-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#544360

On Sunday, January 10, 2016 at 4:31:06 PM UTC-8, ji...@specsol.spam.sux.com wrote:

> 1. The poster is a cut and paste spamming ass hat.

Almost certainly this is incorrect... he more likely performs a "copy and paste"... and more than likely, you yourself probably copy and paste your exact same answer over and over again, making you no better than him... just an observation of the obvious...

[toc] | [prev] | [next] | [standalone]

#544365

pnalsing@gmail.com wrote:
> On Sunday, January 10, 2016 at 4:31:06 PM UTC-8, ji...@specsol.spam.sux.com wrote:
> 
>> 1. The poster is a cut and paste spamming ass hat.
> 
> Almost certainly this is incorrect... he more likely performs a "copy and paste"... and more than likely, you yourself probably copy and paste your exact same answer over and over again, making you no better than him... just an observation of the obvious...

You are diverging from the point.

The ballistics of a bullet in flight are nowhere as simplistic as the cut
and paste article would imply.

Start here for an introduction to the subject:

https://en.wikipedia.org/wiki/External_ballistics

Note that a lot of ballistics comes from statistical, empirical data.

And as for cut and paste:

http://www.yourdictionary.com/copy-and-paste

copy and paste

To make a copy of a file, folder or selected text in another location. The
phrase "cut and paste" is often used when the function is really copy and
paste.


-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#544210

Dne 10/01/2016 v 06:25 pnalsing@gmail.com napsal(a):
> On Saturday, January 9, 2016 at 7:31:07 PM UTC-8, ji...@specsol.spam.sux.com wrote:
> 
>> Except real bullets in air have some lift depending on the bullet shape,
>> cut and paste spamming shit head.
> 
> Well, why don't you just cut and paste a few links that support this statement. I couldn't find a single one myself, perhaps you will have better results.
> 

It should be obvious that the same time applies
to not rotating flat Earth without atmosphere,
with good enough time resolution and precise enough experiment settings.

Major factor causing different time is that air drag is nonlinear,
so for the same vertical speed projections,
the vertical drag force projections are not the same.

Similarly, for fast enough bullet there are tiny effects
of fictitious non inertial Coriolis and centrifugal forces,
together with rotation of a bullet.

-- 
Poutnik ( the Czech word for a wanderer )

Knowledge makes great men humble, but small men arrogant.

[toc] | [prev] | [next] | [standalone]

#544220

I just wish the author knew
the difference between affect and effect.

[toc] | [prev] | [next] | [standalone]

#544316

jimp@specsol.spam.sux.com wrote:
> Sam Wormley <swormley1@gmail.com> wrote:
>> MythBusters: Bringing on the physics bullet drop
>>> http://www.wired.com/2009/10/mythbusters-bringing-on-the-physics-bullet-drop/
>>> If you didn?t catch the latest MythBusters (yeah! new episodes), they
>>> did something straight from the physics textbooks. Just about every
>>> text has this example of shooting a bullet horizontally and dropping
>>> a bullet from the same height. The idea is that they should hit the
>>> ground at the same time. No one but the MythBusters could actually
>>> show this demo with a real gun.
>>> The Physics
>>> I am going to do some calculations, but I want to first write about
>>> the physics that accompanies this idea (and you can actually do it
>>> your self without the gun). What physics principle does this demo
>>> show? Well, it shows two things. First, it shows that the horizontal
>>> and vertical motion in projectile motion are independent. That is,
>>> what happens in the y-direction, stays in the y-direction. Really,
>>> you can treat projectile motion as two separate problems that just
>>> happen to take the same amount of time. The second thing it shows is
>>> that the velocity in one direction does not effect the velocity in
>>> the other direction (which really is the same as the first thing).
>>> Let me draw two diagrams, one for a dropped ball and one for ball
>>> shot horizontally.
> Except real bullets in air have some lift depending on the bullet shape,
> cut and paste spamming shit head.

Here's your data:

https://en.wikipedia.org/wiki/Range_table


--
[80 IQ:]

<http://en.wikipedia.org/wiki/File:2000_Year_Temperature_Comparison.png>

Anybody with a I.Q. level of 80 or higher can see that what we are 
experiencing right now... is perfectly normal on this planet.. 
-- Catoni aka Robert Williamson, 20 Dec 2013

[toc] | [prev] | [next] | [standalone]

#544339

R Kym Horsell <kym@kymhorsell.com> wrote:
> jimp@specsol.spam.sux.com wrote:
>> Sam Wormley <swormley1@gmail.com> wrote:
>>> MythBusters: Bringing on the physics bullet drop
>>>> http://www.wired.com/2009/10/mythbusters-bringing-on-the-physics-bullet-drop/
>>>> If you didn?t catch the latest MythBusters (yeah! new episodes), they
>>>> did something straight from the physics textbooks. Just about every
>>>> text has this example of shooting a bullet horizontally and dropping
>>>> a bullet from the same height. The idea is that they should hit the
>>>> ground at the same time. No one but the MythBusters could actually
>>>> show this demo with a real gun.
>>>> The Physics
>>>> I am going to do some calculations, but I want to first write about
>>>> the physics that accompanies this idea (and you can actually do it
>>>> your self without the gun). What physics principle does this demo
>>>> show? Well, it shows two things. First, it shows that the horizontal
>>>> and vertical motion in projectile motion are independent. That is,
>>>> what happens in the y-direction, stays in the y-direction. Really,
>>>> you can treat projectile motion as two separate problems that just
>>>> happen to take the same amount of time. The second thing it shows is
>>>> that the velocity in one direction does not effect the velocity in
>>>> the other direction (which really is the same as the first thing).
>>>> Let me draw two diagrams, one for a dropped ball and one for ball
>>>> shot horizontally.
>> Except real bullets in air have some lift depending on the bullet shape,
>> cut and paste spamming shit head.
> 
> Here's your data:
> 
> https://en.wikipedia.org/wiki/Range_table

Irrelevant to what I wrote.

A glider in calm air has a fixed range for a given starting altitude.


-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#544265

On Saturday, January 9, 2016 at 6:54:27 PM UTC-8, Sam Wormley wrote:
> MythBusters: Bringing on the physics bullet drop
> > http://www.wired.com/2009/10/mythbusters-bringing-on-the-physics-bullet-drop/
> 
> 
> > If you didn't catch the latest MythBusters (yeah! new episodes), they
> > did something straight from the physics textbooks. Just about every
> > text has this example of shooting a bullet horizontally and dropping
> > a bullet from the same height. The idea is that they should hit the
> > ground at the same time. No one but the MythBusters could actually
> > show this demo with a real gun.
> >
> > The Physics
> >
> > I am going to do some calculations, but I want to first write about
> > the physics that accompanies this idea (and you can actually do it
> > your self without the gun). What physics principle does this demo
> > show? Well, it shows two things. First, it shows that the horizontal
> > and vertical motion in projectile motion are independent. That is,
> > what happens in the y-direction, stays in the y-direction. Really,
> > you can treat projectile motion as two separate problems that just
> > happen to take the same amount of time. The second thing it shows is
> > that the velocity in one direction does not effect the velocity in
> > the other direction (which really is the same as the first thing).
> > Let me draw two diagrams, one for a dropped ball and one for ball
> > shot horizontally.
> 


Perhaps if the bullet were fired in a vacuum.

Double-A

[toc] | [prev] | [next] | [standalone]

#544364

Double-A <double-a3@hush.com> wrote:
> On Saturday, January 9, 2016 at 6:54:27 PM UTC-8, Sam Wormley wrote:
>> MythBusters: Bringing on the physics bullet drop
>> > http://www.wired.com/2009/10/mythbusters-bringing-on-the-physics-bullet-drop/
>> > If you didn't catch the latest MythBusters (yeah! new episodes), they
>> > did something straight from the physics textbooks. Just about every
>> > text has this example of shooting a bullet horizontally and dropping
>> > a bullet from the same height. The idea is that they should hit the
>> > ground at the same time. No one but the MythBusters could actually
>> > show this demo with a real gun.
>> > The Physics
>> > I am going to do some calculations, but I want to first write about
>> > the physics that accompanies this idea (and you can actually do it
>> > your self without the gun). What physics principle does this demo
>> > show? Well, it shows two things. First, it shows that the horizontal
>> > and vertical motion in projectile motion are independent. That is,
>> > what happens in the y-direction, stays in the y-direction. Really,
>> > you can treat projectile motion as two separate problems that just
>> > happen to take the same amount of time. The second thing it shows is
>> > that the velocity in one direction does not effect the velocity in
>> > the other direction (which really is the same as the first thing).
>> > Let me draw two diagrams, one for a dropped ball and one for ball
>> > shot horizontally.
> Perhaps if the bullet were fired in a vacuum.
> Double-A


Let's look at the artillery tables I posted a ref to earlier.
It's been hours and I don't think gimp can back up his claims.
So let's check the opposite.

The tables include a lot of redundant data so there is good scope
for developing models and accurately determining whether or not
the "hang time" of a shell is any different from what you'd expect
if you just dropped the thing dead from a given height.

The tables given the flight time and the max height of the shell.
So we use K12 physics, assume the max height occurs somewhere in the middle 
of the flight, and just check if the time to drop a dead shell from
that height is in any way different from the total flight time.
If not, very prima facie evidence there is no lift.
Much more accurate models (we have, after all, the complete flight profile
of the standard shell out to 10 miles or something every 100 yards)
may get something different, but let's see if there is even a prima facie case.

Flight time        2x Drop time from max height
.18             0.223015
.36             0.44603
.55             0.650195
.75             0.849217
.96             1.03408
1.17            1.2215
1.38            1.41926
1.60            1.63122
1.83            1.8525
2.07            2.07416
2.31            2.323
2.56            2.57194
2.81            2.82535
3.07            3.08616
3.24            3.35636
3.61            3.63385
3.59            3.92025
4.17            4.21375
4.46            4.5102
4.75            4.81165
5.05            5.11721
5.35            5.42619
5.65            5.7402
5.95            6.05641
6.26            6.37644
6.57            6.69046
6.88            7.01701
7.19            7.32903
7.51            7.66082
7.84            7.9944

If anything, it seems there is the opposite effect. There seems to be negative lift.
The flight time seems to be less in most cases (29/31) than the time for the 
shell to rise and fall from the given max height.

Anyone want to make a more accurate model, feel free.

I won't hold my breath for the guys reactively poo-pooing everyone and everything else.

-- 
[Defunding inconvenient science:]
My constituents should not have to continue to foot the bill for an 
organization to keep producing corrupt findings that can be used as 
justification to impose a massive new energy tax on every American
-- Rep Blaine Leutkemeyer (R-MO), 18 Feb 2011

[toc] | [prev] | [next] | [standalone]

#544387

R Kym Horsell <kym@kymhorsell.com> wrote:
> Double-A <double-a3@hush.com> wrote:
>> On Saturday, January 9, 2016 at 6:54:27 PM UTC-8, Sam Wormley wrote:
>>> MythBusters: Bringing on the physics bullet drop
>>> > http://www.wired.com/2009/10/mythbusters-bringing-on-the-physics-bullet-drop/
>>> > If you didn't catch the latest MythBusters (yeah! new episodes), they
>>> > did something straight from the physics textbooks. Just about every
>>> > text has this example of shooting a bullet horizontally and dropping
>>> > a bullet from the same height. The idea is that they should hit the
>>> > ground at the same time. No one but the MythBusters could actually
>>> > show this demo with a real gun.
>>> > The Physics
>>> > I am going to do some calculations, but I want to first write about
>>> > the physics that accompanies this idea (and you can actually do it
>>> > your self without the gun). What physics principle does this demo
>>> > show? Well, it shows two things. First, it shows that the horizontal
>>> > and vertical motion in projectile motion are independent. That is,
>>> > what happens in the y-direction, stays in the y-direction. Really,
>>> > you can treat projectile motion as two separate problems that just
>>> > happen to take the same amount of time. The second thing it shows is
>>> > that the velocity in one direction does not effect the velocity in
>>> > the other direction (which really is the same as the first thing).
>>> > Let me draw two diagrams, one for a dropped ball and one for ball
>>> > shot horizontally.
>> Perhaps if the bullet were fired in a vacuum.
>> Double-A
> 
> 
> Let's look at the artillery tables I posted a ref to earlier.
> It's been hours and I don't think gimp can back up his claims.
> So let's check the opposite.
> 
> The tables include a lot of redundant data so there is good scope
> for developing models and accurately determining whether or not
> the "hang time" of a shell is any different from what you'd expect
> if you just dropped the thing dead from a given height.
> 
> The tables given the flight time and the max height of the shell.
> So we use K12 physics, assume the max height occurs somewhere in the middle 
> of the flight, and just check if the time to drop a dead shell from
> that height is in any way different from the total flight time.
> If not, very prima facie evidence there is no lift.

A glider in equilibrium has a given range for a given initial condition and
a glider certainly has lift.

Ballistic tables just give a range for an initial condition and say
nothing about the how or why the results happen.

Also you continue to ignore the fact that the verticle drag of a dropped
projectile is in general different then that of a fired projectile and
that fact is blazingly obvious.


-- 
Jim Pennino

[toc] | [prev] | [next] | [standalone]

#544391

A dropped one would flutter

[toc] | [prev] | [standalone]

Back to top | Article view | sci.physics

csiph-web