Physics question

wrote in message
ups.com...

You're still assuming he's leading the ME-109 as if the gunner
were in a fixed location. He's assuming the gunner is actually
trying to hit the plane, and smart enough to figure out how
so that he times his shot *correctly*. You're both assuming
he fires straight back. He can hit the Me-109 by firing straight
back, but ONLY if he fires exactly as B-17 crosses the flight
path of the Me-109, and only if the Me-109 is fast enough or
close enough to get there before the bullet drops out of the
flight path of the Me-109. If the Me-109 is at a range of 50
yards, and no slower than the bullet the bullet will be no
more than 7 inches lower than the muzzle of the gun and will
still hit the Me-109 assuming the two planes are at the same
altitude.

Fred...............

I'll say it again - you misunderstand the question. I have stated it as
clearly as I am able and even drawn a diagram. I don't know how else to
explain it. I'm a pilot. I talk with my hands (hopefully without resorting
to certain gestures).

The B-17 is flying West. The ME-109 is flying South. They are both at the
same altitude. There is no wind. The ME-109 will cross the flight path of
the B-17 and the B-17 will, at that moment, be fifty yards from the ME-109.
The tail gunner fires his weapon straight behind the B-17.

There is no way that he can hit the ME-109, given the stated speed of the
B-17 and the muzzle velocity of the bullet.

The ME-109 will *always* be fifty yards or more away from the bullet.
Always.

Rich S.

wrote in message
ups.com...

The gunner cannot hit the ME-109 given those relative positions
and trajectories no matter where he aims.

That is the correct answer.

If the gunner fires straight back when he is at the aiming point
(e.g. re-lable 'aiming point' to be 'firing point' then the bullet
will drop straight down from that point, right?

If you change the question you may have any answer you wish.

Rich "So, we agree?" S.

Here's a wacky scenario... why can you fire a gun on the equator
in the direction of the setting sun? I mean, the Earth spins at
the equator at around 1,000 miles per hour (24,000 mile circum-
ference divided by 24 hr rotation), so why does the bullet exit
the barrel at the same velocity no matter what direction you
point it in? Hmmm. :-)

I think it's because the atmosphere is rotating at the same speed,
thus no friction to slow it down or keep it inside the barrel.

Yes? No? How does this differ from the first scenario?







Dean A. Scott, mfa
---------------------------------------
School of Visual Art and Design
southern adventist university
---------------------------------------
http://www.southern.edu/~dascott

wrote)
Won't it drop stairght down toward the manhole cover? (Yes it will.)


Gads, you're right! Crap, now it's basically T-ball at the manhole cover.
There goes my 1.35 ERA!!


Montblack

Rich S. wrote:
wrote in message
ups.com...

You're still assuming he's leading the ME-109 as if the gunner
were in a fixed location. He's assuming the gunner is actually
trying to hit the plane, and smart enough to figure out how
so that he times his shot *correctly*. You're both assuming
he fires straight back. He can hit the Me-109 by firing straight
back, but ONLY if he fires exactly as B-17 crosses the flight
path of the Me-109, and only if the Me-109 is fast enough or
close enough to get there before the bullet drops out of the
flight path of the Me-109. If the Me-109 is at a range of 50
yards, and no slower than the bullet the bullet will be no
more than 7 inches lower than the muzzle of the gun and will
still hit the Me-109 assuming the two planes are at the same
altitude.

Fred...............

I'll say it again - you misunderstand the question. I have stated it as
clearly as I am able and even drawn a diagram. I don't know how else to
explain it. I'm a pilot. I talk with my hands (hopefully without resorting
to certain gestures).

The B-17 is flying West. The ME-109 is flying South. They are both at the
same altitude. There is no wind. The ME-109 will cross the flight path of
the B-17 and the B-17 will, at that moment, be fifty yards from the ME-109.
The tail gunner fires his weapon straight behind the B-17.

There is no way that he can hit the ME-109, given the stated speed of the
B-17 and the muzzle velocity of the bullet.

The ME-109 will *always* be fifty yards or more away from the bullet.
Always.

Rich S.

The way I see it, you are both in agreement. Fred says to hit the 109
he has to fire at the exact time the 17 croses the 109's path. That is
correct. In effect he says that to fire as per your example he can't
hit it.

Harry K

wrote:
He misses the ME-109 because the recoil of firing the bullet
accelerates the B-17 just a bit, so that the bullet, travelling at a
little less than the bomber's speed actually briefly follows the bomber
as it falls.

A related question: Haven't there been cases of supersonic
fighters shooting themselves down when they caught up to the shells
they'd fired forward?

Dan

I was hoping someone would answer that. I recall seeing/hearing/reading
somewhat the same thing back when. Best I can recall it involved an
F-86 or equivalent (not supersonic) and happened by firing and then
going into a dive thus flying into the bullet stream. Are 50 cal
bullets supersonic?
If so, the plane would also have to be.

Harry K

("Dean A. Scott" wrote)
Here's a wacky scenario... why can you fire a gun on the equator
in the direction of the setting sun? I mean, the Earth spins at
the equator at around 1,000 miles per hour (24,000 mile circum-
ference divided by 24 hr rotation), so why does the bullet exit
the barrel at the same velocity no matter what direction you
point it in? Hmmm. :-)


Don't have an answer ...but pointy bullet shaped things + the equator = this
link.

http://www.qrg.northwestern.edu/projects/vss/docs/Navigation/2-why-launch-from-equator.html
"Why is it better to launch a spaceship from near the equator?"


Montblack

In article .com,
"Harry K" wrote:

wrote:
He misses the ME-109 because the recoil of firing the bullet
accelerates the B-17 just a bit, so that the bullet, travelling at a
little less than the bomber's speed actually briefly follows the bomber
as it falls.

A related question: Haven't there been cases of supersonic
fighters shooting themselves down when they caught up to the shells
they'd fired forward?

Dan

I was hoping someone would answer that. I recall seeing/hearing/reading
somewhat the same thing back when. Best I can recall it involved an
F-86 or equivalent (not supersonic) and happened by firing and then
going into a dive thus flying into the bullet stream. Are 50 cal
bullets supersonic?
If so, the plane would also have to be.

Harry K

No it wouldn't.

Quick question: what does a plane have that a bullet lacks?

Answer: an engine to maintain its speed.

Bullets start slowing down the moment they leave the muzzle (alright,
just slightly *after* they leave the muzzle), while the aircraft that
fired them can maintain its speed.

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling 4 feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect
if you sit in the bottom of that cupboard."

Rich S. wrote:

There is a (magic) B-17 flying along at 560 mph. The tail gunner is out of
.50 caliber ammo. He sees a Messerschmitt ME-109 crossing behind the B-17,
50 yards away.

He pulls out his trusty .45 Colt auto (muzzle velocity 820 fps) and fires at
the Hun when the ME-109 is directly behind the B-17. He leads the
Messerschmitt by exactly enough to hit the pilot (if he were firing from a
fixed position).

Does the bullet exit the muzzle and fall directly to earth?

Rich "Scratching my head" S.


Forgetting turbulence following the B-17 the bullet would still have
a muzzle velocity of 900 FPS, assuming a military load. 50 yards is 50
yards and the Me109 would still be hit assuming proper aim. Whether it
does much more than penetrate the canopy I don't know. Put the trailing
turbulence back into the scenario and all bets are off.

Dan, U.S. Air Force, retired

Blueskies wrote:

But just imagine, as the bullet falls to earth, it will remain horizontal for a while due to the gyroscopic spin caused
by the rifling...


No, the bullet will start dropping due to gravity immediately upon
exiting the muzzle.

Dan, U.S. Air Force, retired