Christmas Conundrum

[Thanaton23]

Hi all, not been here for a while but I did dust off the Alecto today for some snow blasting when something crossed my mind....

If you take an airgun, shooting at say 600fps, and mount it pointing rearwards to say, a plane which also travels at 600fps, when shot, will the pellet:

a) fire rearwards at 600fps?

b) fire rearwards slower than 600fps?

c) slide out the end of the barrel and drop to the ground?

All speeds are relative to a static observer on the ground and turbulence caused by the plane is disregarded since it is only a narrative mechanism.

Please vote and provide a rationale for your selection...

[magicniner]

To a static observer on the ground the pellet will appear stationary as it exits the barrel and will drop to the ground under gravity.
This is because at the speeds under consideration Newtonian Physics suffices and vectors can be added
It won't "Slide" from the end of the barrel as such because it will still be moving at 600fps relative to the muzzle, it will be deflected sideways slightly in it's fall as it will be a rapidly spinning,
ATB,
Nick

[ikarma70]

To a static observer on the ground the pellet will appear stationary as it exits the barrel and will drop to the ground under gravity.
This is because at the speeds under consideration Newtonian Physics suffices and vectors can be added
It won't "Slide" from the end of the barrel as such because it will still be moving at 600fps relative to the muzzle, it will be deflected sideways slightly in it's fall as it will be a rapidly spinning,
ATB,
Nick

Smartarse

[Thanaton23]

To a static observer on the ground the pellet will appear stationary as it exits the barrel and will drop to the ground under gravity.
This is because at the speeds under consideration Newtonian Physics suffices and vectors can be added
It won't "Slide" from the end of the barrel as such because it will still be moving at 600fps relative to the muzzle, it will be deflected sideways slightly in it's fall as it will be a rapidly spinning,
ATB,
Nick

Ahhh, but the coefficient of drag, both in the barrel and after exiting the barrel, would be less. Therefore I argue the second option...

Disregard for turbulence only applies to the aircraft remember.

[HW100/90]

The pellet will fire at 600ft/sec just as it would if you were in your garden.......after all the earth is travelling through space at 25,000 miles an hour (or something like that) and that doesn't affect velocity of your airgun fired in the garden!

Logically, if you had an air pistol and fired it at a target set in the back of the plane, you can't seriously think some matrix like force will see the pellet drop out of the end of the barrel and plop on the floor! Otherwise you wouldn't be able to walk down the plane in flight would you?! I don't know anybody who can walk at 600ft/sec either, but you sure can walk down the aisle on a plane!

[magicniner]

Gentlemen, the important bit here is who's frame of reference should be used, the OP states that we take the frame of reference of a static ground based observer.
He also states that the aircraft is moving at 600fps and the gun is fired backwards & discharges the projectile at 600fps.
The speed of the pellet as it leaves the pistol is stated - no point in trying to factor in barrel friction or air resistance, the speed of the pellet is given
HTH,
Nick

[magicniner]

The pellet will fire at 600ft/sec just as it would if you were in your garden.......after all the earth is travelling through space at 25,000 miles an hour (or something like that) and that doesn't affect velocity of your airgun fired in the garden!

Logically, if you had an air pistol and fired it at a target set in the back of the plane, you can't seriously think some matrix like force will see the pellet drop out of the end of the barrel and plop on the floor! Otherwise you wouldn't be able to walk down the plane in flight would you?! I don't know anybody who can walk at 600ft/sec either, but you sure can walk down the aisle on a plane!

The OP states that the gun is mounted TO the plane and fires backward, we're asked what the ground based observer sees.

Had the gun been fired IN the plane at a target at the back of the cabin then the plane AND the target are moving forward at 600fps relative to the ground and the pellet moves backward at 600fps realtive to the plane so the ground based observer still sees a stationary pellet dropping under gravity with a little bit of forward acceleration from drag from the air in the cabin
Enjoy!
Nick

[magicniner]

Ahhh, but the coefficient of drag, both in the barrel and after exiting the barrel, would be less. Therefore I argue the second option...

Disregard for turbulence only applies to the aircraft remember.

600fps is stated - that's AS it leaves the barrel

[dahaloguy]

Classic Physics Thought Experiment.

The two forces would cancel each other out and the pellet would drop but only in a perfect Newtonian world.

They did it on mythbusters last year. They also tested
"if one bullet is fired horizontally and the other is dropped vertically, simultaneously from the same height, which will hit the ground first? Or will they hit at the same time, owing to gravity"

[Thanaton23]

600fps is stated - that's AS it leaves the barrel

Ok Nick, upon reading, it does seem like that's what I meant. In my head what I meant was that the gun normally fires at 600fps, say, in your garden. I don't want to seem like I am changing the goalposts, so I concede that you are technically correct....

It would still fire backwards tho......

[essjay]

You didn't say what the airgun was.
If it was your Alecto, it could never reach 600fps, so nothing would happen.
If it did, this would be a Section 5 firearm and illegal and would never be allowed on a plane.

[Vic Thompson]

I'm ready to be shot down in flames, but here's my opinion : in an atmosphere, not so in space, my guess is that the observer would see the pellet move in a rearward direction relative to the line of flight of the aircraft, at a velocity of less than 600 fps, due to "imparted velocity from the air flow" cause by movement of the plane through the atmosphere (analogous to firing a pellet on the ground in the direction of a breeze (in the direction of the breeze the pellet speeds up, against the breeze, the pellet slows down (relative to a fixed point on the ground)).

Vic T

[layabout]

Yea,......right, got it ! .......hang on, explain that again

[magicniner]

I'm ready to be shot down in flames, but here's my opinion : in an atmosphere, not so in space, my guess is that the observer would see the pellet move in a rearward direction relative to the line of flight of the aircraft, at a velocity of less than 600 fps, due to "imparted velocity from the air flow" cause by movement of the plane through the atmosphere (analogous to firing a pellet on the ground in the direction of a breeze (in the direction of the breeze the pellet speeds up, against the breeze, the pellet slows down (relative to a fixed point on the ground)).

Vic T

The OP stated

All speeds are relative to a static observer on the ground and turbulence caused by the plane is disregarded since it is only a narrative mechanism.