Firing a bullet out of a train

[joewetherill]

If you got on a train that went exactly the same speed as a bullet comes out of a gun. What would heppen if you fired then gun forwards out of the window of the train?

Would it go twice as fast as normal of would it not move at all?!

Furthermore, what would happen if you fired the gun backwards up the outside of the train.

Thanks for your time
Joe

[gen2]

Relative to the gun, the bullet leaves it at the same speed whichever direction it is pointed in.

Relative to an observer on the ground (not on the train), a bullet fired forwards will initially travel at (firing velocity + train's velocity). A bullet fired backwards will travel at (firing velocity - train's velocity).

[Loosehead]

Ok to field the pedants we'll ignore the air for the purposes of this explanation. If you are in a train doing 500mph and you fire a bullet forward at 500mph the bullet will be doing 1000 relative to the ground 500mph relative to the train. If you fire it back wards it will drop still on the floor behind the train.

[bernardo]

Yes it would go at twice the speed of the train (relative to someone standing on the gound).

Backwards: yes, the bullet would have no speed sideways and would fall limply to the ground.

In reality, the speed of a bullet coming from a gun is something like 2000 feet per second; it would be virtually impossible to get a train up to that speed in the first place because of the high air resistance.

[chainfire]

Sorry, this is a deviation of the question, but as it's already answered: Has anyone been injured/killed by bullets that have been shot into the air and then fallen. I know that the odds of it happen are quite low, but still, has there been any reported incidents?

[Birt]

I have heard some planes have shot themselves down. Diving at fast speeds and firing they then ran into the bullets damaging wings etc.

[stevie21]

chainfire - it happened on CSI once :-)

[Toureman]

To answer chainfire's question, it is highly unlikely they would kill anyone, more likely to be killed or injured by a large hail stone.

The light calibre bullet would go up to it's maximum height then stop and FALL back down, it would be too light to cause serious injury or death.

[chainfire]

found this website: http://www.villman.com/forums/topic.asp?TOPIC_ ID=1087

[isj032]

Maybe i'm wrong here, but putting the train/bullets velocity aside for a moment, wouldn't the determining factors be the mass of the objects in question, the air difference in air resistance thus implied. How would the trains' 'slip stream', affect the answer if the bullet was fired behind? Please excuse grammar.