# Physicists.. can you help settle a dispute.

Another way to look at it is that the projectile is travelling at the same speed as the train, until you apply a force to cancel it’s velocity.

I get it, a gun like device, on some sort of vehicle which runs on tracks.
Man, we could really solve this thing!!!

OK, OK, maybe it wasn’t that revolutionary of a plan to simplify the whole thing, but I felt that we’re getting all tied up with the idea that a train as fast as a bullet would be really fast and would generate loads of turbulence and that bullets are really small and so on.

On the remote possibility that you have access to JATO rocket, might I suggest something like this? (google cache, site is down right now)

It’s a good read anyway if (IMHO) purely fiction.

Sorry for the hijack.

Lets call the speed of the bullet 500mph. The train is moving at the speed of the bullet , or 500mph already, relative to the earth. The bullet is then fired at 500mph in the opposite direction. The bullet is now travelling at a speed of 500mph relative to the train. The bullet must, at the time of firing, be stationary relative to the earth:

500 - 500 = 0

The bullet then drops to the ground and is at the affected by any air movement on it’s short trip downwards.

The bullet would certainly not be affected by a tail wind. The bullet would be affected by the slipstream of the train which would be a headwind for the bullet. This would cause the bullet to travel slightly in the direction of the train.

Thanks guys. So the answer is, more or less, the bullet will fall straight down, from the point of view of a stationary observer.

Emphatically yes.
[sup](More or less)[/sup]