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The velocity of a bullet fired from the back of a train

1 points by mikecane ↗ HN
This is from an issue of The American Magazine. Is it true?

15. If a man is standing on the back platform of a railroad train which is traveling at the rate of sixty miles an hour, and fires a bullet in the direction from which the train came, and the powder back of it is capable of driving the bullet sixty miles an hour, what will happen to the bullet?

The velocity at which the bullet, as part of the train, is traveling, will be overcome by the force given it by exploding the powder, operating in the opposite direction, and it will drop to the ground.

4 comments

[ 4.7 ms ] story [ 23.8 ms ] thread
asdlfkk
Yes it will - that's basic relativity. From the point of view of the person firing the gun it will look entirely normal - as if it's flying off into the distance. Only from the point of view of someone on the ground will it appear to just fall.

However... a bullet normally travels around 2000 fps, 1363 mph. Even the slowest bullets still travel 700 mph or so. So you wouldn't see it in practice.

mikecane
Yeah, that's what tripped me up, the actual speed of the bullet in real life. Thanks.
frozen11b
Myth busters did this a few years back with a basket ball in an air cannon tied to the back of a truck going 55 mph and the cannon set to fire the basket ball at exactly 55 mph. The ball goes no where as one relative force cancels out the other.