Poll: Bullet physics, the two trains

[spartan231490]

The wind resistance of the two slip-streams would push the bullet off target, but it's impossible to know how much without knowing how fast the trains are going and how large they are.

Hm didn't even think about that. Considering the sceene in the game was in a tunel as well, the air flow would be interesting to say the least. No idea what something like that would do to a bullet.

Yes it is small and travels fast, but then it's also rather light.

I would say yes you would have to lead the target. In the sport of biathlon the range length is 50 meters but they have zero weapons in just normal winds speed of 10 metres per second which is 2 to 4 times less that forward motion of passenger train. If you think about for second, take the trains out of it and imagine you are trying to shoot a target with a hurricane force cross wind, you would have to correct for it.

When I try to picture standing there in a hurricane trying to hit a target, I start to think it would actually miss because of it.

If we know how long a bullet has been in the air after traveling 20m, and then found out how much sideways force the wind would be able to apply during that time, would that not give us the answer? Or doesn't it work that way?

It would, but there are several problems to figuring that out. The time is fairly easy to find, if you know the weapon used, but the force exerted by the wind is something else entirely. You would need the drag coefficient, but the drag coefficient you would find on the internet would be the drag when the wind goes over the bullet front to back. This is used by shooters everywhere to determine a lot of things about long range shooting. The problem is that this coefficient would be very different from the drag coefficient for a side-on bullet. I don't know if you could find that drag coefficient.

That said, even knowing the drag coefficient, the math would be very difficult considering that a slipstream does not have consistent wind speeds or pressures. Laminar flow would be in effect, consisting of several layers of air at different pressures and speeds. I would even go so far as to say you couldn't model this mathematically. To get an accurate answer you would probably need to do wind-tunnel testing of some kind.