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A simple ballisitcs question:

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Does firing a bullet against the wind or with the wind affect bullet drop or does it make no difference?  

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I should imagine that IRL it necessarily makes a difference but even there it must be close to negligible - specially so because they spend little time flying so there is not enough time for the wind to play a significant part. In-game, however, is a good question, and I would add more: the flight model for bullets is the same for other objects, or they all have their own separate set of physics? If separate, the bullets fly in a wind-less world?

Edited by danielprates

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For aerial gunnery (an aircraft shooting at another aircraft) wind has zero influence, because both aircraft are moving with the wind, essentially they are both inside a "block" of air that's moving pretty much uniformly relative to the ground. Therefore there is largely no wind around an aircraft in flight, and the only airflow is created by the aircraft movement through the "block" of air. 

 

Wind has a huge impact on air-to-ground gunnery though. 

Edited by Finkeren
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19 minutes ago, Finkeren said:

wind has zero influence, because both aircraft are moving with the wind

 

Yes but, as soon as the bullet leaves the airplane, it becomes its own distinct flying object, with its own different aerodynamic profile. Wind is bound to have different effects on different aerodynamic profiles: if one is extrelly streamlined and the other isn't, the wind won't carry them together. I accept that the effect is close to none, this may be mere splitting hairs, but it cant be correct that wind plays no part just because the ammo and the plane it left from are inside the same wind.

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Fired  at a 45 degree up angle there is a little less bullet drop. The bullet is moving forward as well as upward. The forward motion exposes the side of the bullet to the air.

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52 minutes ago, danielprates said:

but it cant be correct that wind plays no part just because the ammo and the plane it left from are inside the same wind.

It is correct (relative to the plane). If you consider the movement of the bullet and the plane relative to each other. For example, if there is a 300mph wind and an aircraft at max speed of 300mph is flying directly into it, the plane will be stopped relative to the ground, and the bullets it fires will be slower relative to the round (by 300mph) than a plane fling at 300mph away from that same wind. In fact the bullets will be going 300mph faster, but *relative to the plane* the bullets will have exactly the same behaviour in both instances.

Because what Finkeren said.

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OK assuming that the person firing the bullet is stationary and firing over a long distance, what effect does it have if any?

 

Besides that, yes, it is an aerial gunnery question I ask.  Here's the scenario that prompted my curiosity:

 

Last night I was flying on a server map that had "Strong winds coming from the North" in it's mission description tab.  Windsocks at the airfield were pretty much stretched to their limit be a wind heading near-perfectly from 000 degrees to 180 degrees.  

 

I attacked ground targets by strafing at a shallow (10 degrees, I estimate) angle.  When I attacked from North to South, It appeared to me that my bullets would go a bit long and miss the target. From South to North, some shots fell short.  It was only a matter of +/- 10 feet either way, but it was enough to notice.  

 

And before you ask, I am very confident with ground strafing targets straight on and mostly confident with ground strafing that requires heavy rudder use to counter crosswind.     

Edited by Mobile_BBQ

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7 minutes ago, Mobile_BBQ said:

OK assuming that the person firing the bullet is stationery and firing over a long distance, what effect does it have if any?

 

If he fires one bullet  into the wind (a) and one away (b), although the momentum of the bullets when fired are equal bullet a will slow down faster, as because its airspeed is greater, it will incur more drag (drag is proportional to some function of speed). Their initial speed relative to the ground will be equal but, all things being equal, (a) will have a shorter flight time.

 

Now in the air, because the aircraft is already moving at the same speed relative to the air whether it's moving into wind or not (only the groundspeed is different). The bullets also have the same speed therefore same drag therefore same deceleration therefore same flight time.

 

 

12 minutes ago, Mobile_BBQ said:

OK assuming that the person firing the bullet is stationery and firing over a long distance, what effect does it have if any?

 

Besides that, yes, it is an aerial gunnery question I ask.  Here's the scenario that prompted my curiosity:

 

Last night I was flying on a server map that had "Strong winds coming from the North" in it's mission description tab.  Windsocks at the airfield were pretty much stretched to their limit be a wind heading near-perfectly from 000 degrees to 180 degrees.  

 

I attacked ground targets by strafing at a shallow (10 degrees, I estimate) angle.  When I attacked from North to South, It appeared to me that my bullets would go a bit long and miss the target. From South to North, some shots fell short.  It was only a matter of +/- 10 feet either way, but it was enough to notice.  

 

And before you ask, I am very confident with ground strafing targets straight on and mostly confident with ground strafing that requires heavy rudder use to counter crosswind.     



By firing against a ground target, from a plane in a moving body of wind, the wind *does* matter because it's not just the bullets' movement relative to the plane that matters, but also the fact that the target although stationary relative to the ground it is moving relative to the wind, in terms of the mathematics of it. 

 

There are some assumptions here, eg Coriolis effect does affect bullets, and actually has to be taken into account in some forms of gunnery, but can be ignored in examples like this, also turbulence etc.

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When shooting air-to-ground, if you keep your airspeed constant you'll get less bullet drop firing downwind, because the wind is added to your airspeed, meaning the bullet gets there sooner - resulting in less drop. Firing upwind, you are travelling slower, so the bullet takes longer - more drop. I'm surprised the effect is enough to be noticeable though.

Edited by AndyJWest
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8 hours ago, Mobile_BBQ said:

Does firing a bullet against the wind or with the wind affect bullet drop or does it make no difference?  

Yes it does affect the bullet, if the target is not affected by the wind (ie a fixed ground target)

 

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47 minutes ago, 71st_AH_Barnacles said:

 

….it is moving relative to the wind, in terms of the mathematics of it. 
 

 

I see what you are saying, but I would think that that the primary relationship that would be factored into the equation would be wind relative to the ground not the other way around. As far as the target's relationship to the ground, I view it as "If it's on the ground, it is the ground.", albeit a specific fixed point on the ground. 

52 minutes ago, AndyJWest said:

 I'm surprised the effect is enough to be noticeable though.

 

It was definitely noticeable.  I was applying my normal shooting style to the target, which allows me to normally hit at about 300m away with a 1-click burst.  Not to blow my own horn, but I've gotten quite good at it.  The bullets were either hitting the sandbags in front of the AA guns or flying over the position to hit just behind depending on the heading relative to the wind I was on.  I can say for certain that the "sight picture" appeared to be correct, but in reality, it was only correct for lesser wind and turbulence conditions.  

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2 minutes ago, Mobile_BBQ said:

 

I see what you are saying, but I would think that that the primary relationship that would be factored into the equation would be wind relative to the ground not the other way around. 

Mathematically you can consider the ground fixed (speed = 0) or the body of air fixed. Therefore the ground can be considered to be moving for the purposes if working out the ballistics, depending on what you consider 'fixed'. It really doesn't matter, it just helps sometimes to visualise what's going on.

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9 minutes ago, 71st_AH_Barnacles said:

Mathematically you can consider the ground fixed (speed = 0) or the body of air fixed. Therefore the ground can be considered to be moving for the purposes if working out the ballistics, depending on what you consider 'fixed'. It really doesn't matter, it just helps sometimes to visualise what's going on.

 

Roger that.  It sometimes seems strange that depending on relative point of view, it could actually be the wind that is considered to be stationary.  

Edited by Mobile_BBQ

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4 hours ago, danielprates said:

 

Yes but, as soon as the bullet leaves the airplane, it becomes its own distinct flying object, with its own different aerodynamic profile. Wind is bound to have different effects on different aerodynamic profiles: if one is extrelly streamlined and the other isn't, the wind won't carry them together. I accept that the effect is close to none, this may be mere splitting hairs, but it cant be correct that wind plays no part just because the ammo and the plane it left from are inside the same wind.

 

No, it won't work like you say, because for a plane in flight, wind speed only affects ground speed, not air speed. Once you get a little above treetop altitude, wind generally blows rather uniformly and steadily from one direction. This means that any aircraft flying through the air is carried away by the wind, without the wind being felt by the plane at all. Effectively there is no wind blowing around an aircraft in flight - only as relates to ground speed. The same will go for any projectile fired from said aircraft. 

 

It is a bit easier to understand, if you have ever flown in a hot air ballon (an un-tethered one) . Once it takes off it is carried off by the wind, quickly matching the speed and direction of the wind, and suddenly the air around the balloon seems to become extremely calm, as if no wind is blowing at all, and often you can hear noises from the ground with almost unnatural clarity. If you were to fire a gun from a hot air balloon, the bullet would move as if there was no wind as viewed from the balloon. Since there is effectively no wind blowing, it can't affect the bullet and the balloon differently. 

 

The exact thing happens to an airplane, but since the plane is not just drifting with the wind but moving under its own power at several hundred mph through the air, the lack of wind is not really felt. 

Edited by Finkeren
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sit in the back of a jumbo jet on a windy day and ask them to turn off yaw dampner you will be violently ill.
wind is felt 

 

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25 minutes ago, Finkeren said:

 

No, it won't work like you say, because for a plane in flight, wind speed only affects ground speed, not air speed. Once you get a little above treetop altitude, wind generally blows rather uniformly and steadily from one direction. This means that any aircraft flying through the air is carried away by the wind, without the wind being felt by the plane at all. Effectively there is no wind blowing around an aircraft in flight - only as relates to ground speed. The same will go for any projectile fired from said aircraft. 

 

It is a bit easier to understand, if you have ever flown in a hot air ballon (an un-tethered one) . Once it takes off it is carried off by the wind, quickly matching the speed and direction of the wind, and suddenly the air around the balloon seems to become extremely calm, as if no wind is blowing at all, and often you can hear noises from the ground with almost unnatural clarity. If you were to fire a gun from a hot air balloon, the bullet would move as if there was no wind as viewed from the balloon. Since there is effectively no wind blowing, it can't affect the bullet and the balloon differently. 

 

The exact thing happens to an airplane, but since the plane is not just drifting with the wind but moving under its own power at several hundred mph through the air, the lack of wind is not really felt. 

 

Yup, put it like that, it makes indeed more sense. 

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A bullet drops at exactly the same speed whether fired from a gun or simply dropped with no forward velocity. So a head or tailwind would have zero effect on this. 
Bullet drop is how far the round will travel during its gravity induced fall. 
A bullet from a .50 cal MG leaves the barrel at 2,900 fps roughly which is equal to 1,977 mph. So a head or tail wind of even 40mph (on the ground) would make a negligible difference. A tail wind would make the bullet travel farther but only by a very tiny amount. 
Aircraft in flight and shooting at one another don’t experience head or tail wind relative to each other. They’re moving together in the same air mass. The shooting aircraft’s speed is added to the bullets speed so the relative velocity between shooter and target is the same. 
 

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18 minutes ago, SharpeXB said:

A bullet drops at exactly the same speed whether fired from a gun or simply dropped with no forward velocity. So a head or tailwind would have zero effect on this. 
Bullet drop is how far the round will travel during its gravity induced fall

 

This is true. But in the OP, if I understood correctly, he used the term "drop" but was actually asking if the bullet would fall farther or closer. Something that I must admit was plagueing me too until I read Finkeren's later post. 

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1 hour ago, =TBAS=Sschatten14 said:

sit in the back of a jumbo jet on a windy day and ask them to turn off yaw dampner you will be violently ill.
wind is felt 

 

 

That may be true with crosswind.

37 minutes ago, danielprates said:

 

This is true. But in the OP, if I understood correctly, he used the term "drop" but was actually asking if the bullet would fall farther or closer. Something that I must admit was plagueing me too until I read Finkeren's later post. 

 

Yes, I was asking if there was any difference, no matter how slight, in how far a bullet would travel when shot straight-on into a head wind vs shot straight-on with a tail wind.  Both the shooter and the target would be stationary.  

 

Of course, explanations of how it relates, or differs from, aerial gunnery is welcome.   Thanks for the responses!

 

~S~   

 

 

 

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This is the kind of thread that makes this forum so great. Physics/technical knowledge can be counterintuitive sometimes and this forum amasses some very great knowledgeable dudes.

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1 hour ago, Mobile_BBQ said:

Yes, I was asking if there was any difference, no matter how slight, in how far a bullet would travel when shot straight-on into a head wind vs shot straight-on with a tail wind.  Both the shooter and the target would be stationary.  

Well sure a headwind or tailwind would affect a bullet. But the magnitude would be extremely small. Again you’re looking at a bullet traveling about 2,000 mph affected by a wind at maybe 40mph for even a strong wind. 

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7 hours ago, AndyJWest said:

When shooting air-to-ground, if you keep your airspeed constant you'll get less bullet drop firing downwind, because the wind is added to your airspeed, meaning the bullet gets there sooner - resulting in less drop. Firing upwind, you are travelling slower, so the bullet takes longer - more drop. I'm surprised the effect is enough to be noticeable though.

 

That is a question of the ratio of the windspeed to the average projectile speed before impact. Beaufort scale 5 is fresh breeze, 28-38 kph, so it could be enough, if strafing at a shallow angle with a cannon with a lowish MV, but I agree you would usually not notice.

 

When shooting air-to-air you will notice the difference between nose and tail gunners. In this case due to the drag caused by speed of the bullet relative to the air: firing forwards add your plane speed to the MV, firing back subtract it.  Since the drag equation squares velocity, the forwards firing bullets will slow much faster. The  drop per time unit is the same, but the shots backwards will have a flatter trajectory, ie appear to drop more.   

 

1 hour ago, SharpeXB said:

Well sure a headwind or tailwind would affect a bullet. But the magnitude would be extremely small. Again you’re looking at a bullet traveling about 2,000 mph affected by a wind at maybe 40mph for even a strong wind. 

 

Yes, except for the air gunner case, where the speed of a cruising bomber is close to 10% of the MV.  Firing forwards that is 50% more initial drag than firing backwards. 

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37 minutes ago, unreasonable said:

 

Yes, except for the air gunner case, where the speed of a cruising bomber is close to 10% of the MV.  Firing forwards that is 50% more initial drag than firing backwards. 

This would sure be a great one for Mythbusters! 😁

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9 minutes ago, SharpeXB said:

This would sure be a great one for Mythbusters! 😁

 

No need: you can see a fully quantified example of time to target and bullet speed remaining for forwards and backwards fire with a variety of guns in the last appendix of a800394 from the US Ballistics Laboratories, or just work it out the basic principle for yourself.

 

Simply put, V in the drag equations is squared, making drag extremely sensitive to it.   D = Cd * A * .5 * r * V^2

 

Holding everything else constant and using an index figure, if D = 100 when V =100, then if V = 90, D = 81.  If V = 110, D = 121         121/81 = 1.49

 

 

 

 

 

 

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12 hours ago, =TBAS=Sschatten14 said:

sit in the back of a jumbo jet on a windy day and ask them to turn off yaw dampner you will be violently ill.
wind is felt 

 

Turbulence yes, the wind is not. 

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On 2/1/2020 at 10:47 AM, Mobile_BBQ said:

Does firing a bullet against the wind or with the wind affect bullet drop or does it make no difference?  

 

Well, for a proper ballistic calculation all the forces that affect the bullet have to be taken into account:

 

1. gravity. This force is responsible for the bullet drop. On earth's surface it's almost constant. Going up it becomes smaller following a law of inverse squared distance.

 

2. Drag/friction. This force slows the bullet down and therefore adds to the bullet drop. The details are described in the post of <unreasonable>. Since v is the bullet's speed relative to the medium (air), wind will change this speed and should affect the drop. Not mentioned by <unreasonable> is the effect that drag becomes smaller towards larger altitudes due to the thinner air. This can be understood easily since there's not drag at all in vacuum/space. But this not crucial for "surface ballistics".

 

3. Coriolis force. This does not affect bullet drop but snipers know about its importance in long range precision shooting .

 

In reality wind can be neglected if you follow the advice of Erich Hartmann, germany's  WW II top fighter ace:

 

If you think you are close enough for a shot, get closer!

 

He suggested to open fire at 100 meters. Here, the target is huge, making a miss almost impossible and the bullet speed is still high, resulting in higher kinetic energy and a higher destructive power.

 

best regards

 

eastriverman

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16 hours ago, =TBAS=Sschatten14 said:

sit in the back of a jumbo jet on a windy day and ask them to turn off yaw dampner you will be violently ill.
wind is felt 

 

Those are gusts of turbulent air not the wind or one can say turbulence. 

You can play ping pong table game without notice difference at all onboard  air balloon when traveling at any mph wind. Just don't look at the moving ground ;)

Edited by 1PL-Husar-1Esk

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21 hours ago, eastriverman said:

He suggested to open fire at 100 meters. Here, the target is huge, making a miss almost impossible and the bullet speed is still high, resulting in higher kinetic energy and a higher destructive power.

Not to forget, that more bullets will hit the target, because the effect of bullet spread is less, the closer the target is.

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On 2/2/2020 at 6:51 AM, eastriverman said:

3. Coriolis force. This does not affect bullet drop but snipers know about its importance in long range precision shooting .

Are you talking about the rotation of the earth? Because in our case that should be negligible compared to the other sources of error in impact point. Since the shooter and the target are moving at similar relative velocities there's little impact to consider. If shooting north/south at large ranges the difference in these velocities will start to matter, but IIRC the worst-case drop with a .308 round is like 4" at 1000 yards (forgive my garbage units). Generally the drop component of this is the more significant factor than the sideways component (US Army FMs mention only that the drop component is significant and advise neglecting the sideways ones. Though this FM is probably outdated and that same .308 round would move sideways 3" in worst case scenario).  And of course, as time of flight increases the impact of this does increase, which is why aircraft can demonstrate it much better than bullets can. 

 

Otherwise one bullet-wind effect we have to consider for aircraft is the Magnus Effect which impacts a bullet in crosswind making it move up or down depending on the spin of the round and the wind speed. For anyone familiar with the backspin on an Airsoft BB (hop-up) making the BBs fly more level, its the same physics at play. the difference is that with an airsoft BB the spin axis is 90 degrees off of the flight direction, and parallel to the ground. In a bullet the spin axis is along the flight direction so only crosswinds cause the magnus effect in bullets. Alternatively, it's how pitchers in baseball throw curveballs. This effect in particular makes shooting from aircraft, especially rotary-wing aircraft difficult. If firing from the left side of a rotary wing aircraft traveling forward, you might fire and have a round move to your left from the prop wash, then after it gets out of the prop wash it may move down from the oncoming wind.

 

Ballistics is a lot of fun because of how differently everything adjusts point of impact for different cases. Unlike the Coriolis impacts being of little concern to us, but a larger concern to snipers, the Magnus Effect is of large concern to us and supposedly negligible to snipers. Much of this may be irrelevant to our cases since we're starting to get into differences that are much smaller than the typical 0.5-1 MOA (5-10" at 1000 yards) accuracy of modern match-grade sniper rounds, and most firearms in WWII were not nearly this accurate (many bolt-action firearms being around 3-4 MOA accuracy). 

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5 minutes ago, Kataphrakt said:

Are you talking about the rotation of the earth?

Yes.

 

The Coriolis force is a so-called pseudo force present only in an accelerated reference system. For example, the centrifugal force is a pseudo force, too.

 

Where Coriolis force matters is aerial navigation. If you set a straight course from a starting point to a target, the earth with your target point will rotate underneath your straight flight path and you will miss your target if you don't take this into account.

 

Wonder if this is simulated in GB, too......

 

 

 

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3 minutes ago, eastriverman said:

Yes.

 

The Coriolis force is a so-called pseudo force present only in an accelerated reference system. For example, the centrifugal force is a pseudo force, too.

 

Where Coriolis force matters is aerial navigation. If you set a straight course from a starting point to a target, the earth with your target point will rotate underneath your straight flight path and you will miss your target if you don't take this into account.

 

Wonder if this is simulated in GB, too......

 

 

 

I suppose we could test this in QMB. Set no wind, autolevel (or trim an aircraft stably) then fly north or south and check where you end up. 

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26 minutes ago, Kataphrakt said:

Otherwise one bullet-wind effect we have to consider for aircraft is the Magnus Effect which impacts a bullet in crosswind making it move up or down depending on the spin of the round and the wind speed. For anyone familiar with the backspin on an Airsoft BB (hop-up) making the BBs fly more level, its the same physics at play. the difference is that with an airsoft BB the spin axis is 90 degrees off of the flight direction, and parallel to the ground. In a bullet the spin axis is along the flight direction so only crosswinds cause the magnus effect in bullets. Alternatively, it's how pitchers in baseball throw curveballs. This effect in particular makes shooting from aircraft, especially rotary-wing aircraft difficult. If firing from the left side of a rotary wing aircraft traveling forward, you might fire and have a round move to your left from the prop wash, then after it gets out of the prop wash it may move down from the oncoming wind.

 

 

What we learn from this is, that the more you go into detail the more complicated things become.

 

For example, bullet drop due to gravity is larger at sea level than it is on top of Mount Everest (probably illegal to fire a shot there). But even on sea level bullet drop is smaller at the equator than it is at north or south pole since earth's shape is not that of an ideal sphere....

 

And then earth is not made from a homogeneous material. There are regions with different density of matter. Guess what that means for the value of earth's gravity constant g. Actually, there are g-mappings giving you the exact value of g at different places.

 

Do you know if this is taken into account in military ballistics, especially long range shooting like heavy artillery?

 

It's a miracle that we hit anything at all 😀

 

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1 minute ago, eastriverman said:

For example, bullet drop due to gravity is larger at sea level than it is on top of Mount Everest

If you want even more fun, there's the fact that newton's law of gravitation says:

 

Gravitational Force = Gravitational constant * (Mass1 * Mass2)/radius^2

 

So according to physics an object with more mass does, in fact, fall faster than an object with less mass. (though bringing this up to your physics professor when he says two objects fall with the same acceleration will likely not score you any points...)

 

5 minutes ago, eastriverman said:

Do you know if this is taken into account in military ballistics, especially long range shooting like heavy artillery?

I would expect probably not. I'm not an expert on this and only have done a little bit of digging on this kind of thing in the past. Generally, the US doesnt seem to employ long-range artillery in a role of precision, instead for area saturation. I would expect for these cases that most of those really quirky factors are pretty much negligible compared to wind correction and barrel/round accuracy. If something accurate is needed they'd probably use a guided weapon so they can basically just ignore everything.

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There are many factors that affect ballistics, but as far as anything fired from a WW2 aircraft goes, only a few matter that much when you take into account manufacturing tolerances for gun and ammo, and for the fact you are firing from an airframe that flexes under load. 

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1 hour ago, Kataphrakt said:

If you want even more fun, there's the fact that newton's law of gravitation says:

 

Gravitational Force = Gravitational constant * (Mass1 * Mass2)/radius^2

 

So according to physics an object with more mass does, in fact, fall faster than an object with less mass. (though bringing this up to your physics professor when he says two objects fall with the same acceleration will likely not score you any points...)

 

 

You really never do know what you are going to come across on this forum. 😀

 

I'd like to thank you for distracting me from my really important work (not really...) for the last 20 minutes while i researched this....

 

Turns out the answer is down to inertial mass - the increased gravitational force experienced by the heavier object is balanced out exactly by the increased force needed to accelerate it due to its greater inertia. So they do fall at the same speed. 

 

Phew, Newton can rest in his grave....

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1 hour ago, Kataphrakt said:

 

 

So according to physics an object with more mass does, in fact, fall faster than an object with less mass. (though bringing this up to your physics professor when he says two objects fall with the same acceleration will likely not score you any points...)

 

 

F=m*a so that's only true ('falling' faster) if you consider the earth is being attracted to the bullet.

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Usually, bullets seem to be attracted to me.🤣

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8 minutes ago, 71st_AH_Barnacles said:

F=m*a so that's only true ('falling' faster) if you consider the earth is being attracted to the bullet.

Since Newton's laws include "for every action their is an equal and opposite reaction" we do need to consider the earth being attracted to the bullet. Every time you jump, the earth must move down. 

 

9 minutes ago, kendo said:

 

You really never do know what you are going to come across on this forum. 😀

 

I'd like to thank you for distracting me from my really important work (not really...) for the last 20 minutes while i researched this....

 

Turns out the answer is down to inertial mass - the increased gravitational force experienced by the heavier object is balanced out exactly by the increased force needed to accelerate it due to its greater inertia. So they do fall at the same speed. 

 

Phew, Newton can rest in his grave....

Remember newton's laws. For every action there is an equal and opposite reaction. The acceleration that the earth applies on a 600kg object is the same as that which it applies on a 1kg object because of the mass of the object mathmatically canceling out the greater force; however, this somewhat ignores newton's first law since we are neglecting the acceleration of the earth caused by these objects falling. Below is a pair of calculations using an 800kg reference mass then comparing relative accelerations for a 600kg mass and a 1kg mass. We can see that the acceleration of mass 2 caused by mass 1 is exactly the same as the acceleration of mass 3 caused by mass 1; however, the acceleration of mass 1 caused by mass 2 is greater than the acceleration caused on mass 1 by mass 3. If we look at the net acceleration of mass 1 and mass 2 it is greater than the net accelerations of mass 1 and mass 3. This is a fairly pointless thing though, since in the experiments of dropping a feather and a bowling ball at the same time their pull on the earth means that the earth is accelerating towards them at the same rate so they do accelerate with the same net accelerations; however, if you drop one, then after it lands drop the other, they would be different. Also, the acceleration of the earth caused by these objects is absolutely negligible. 😁

 

image.thumb.png.c13f44bcddda81ff09c0e086bdee92c1.png

please excuse the (m/s) instead of (m/s^2) i didnt type that in since it was a quick example. 

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I love this place.

"A simple Ballistics Questions"
20 Posts Later we're interrogating our basic assumptions of Newtonian physics.

Another day or two I fully expect us to have a tutorial on quantum physics in here, followed shortly thereafter by a thread under Developer Assistance insisting the physics engine be updated to include the Heisenberg Uncertainty Principle. 

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2 hours ago, Kataphrakt said:

If you want even more fun, there's the fact that newton's law of gravitation says:

 

Gravitational Force = Gravitational constant * (Mass1 * Mass2)/radius^2

 

So according to physics an object with more mass does, in fact, fall faster than an object with less mass. (though bringing this up to your physics professor when he says two objects fall with the same acceleration will likely not score you any points...)

 

 

The problem with your professor is that you look at two objects of different  mass falling to the earth. Yes they fall at the same velocity relative to each other. If you look at a single object and the Earth what you see is an object falling. What you do not see is that, that object is pulling on the Earth. While the effect is incredible small, the Earth is being pulled towards the falling object. This can be seen with the relationship of the Moon and the Earth. The Moon pulls the Earth "up". This results in Tides. The Earth's oceans are trying to fall to the Moon.

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