# Physicists.. can you help settle a dispute. **URL:** \ **Category:** Factual Questions\ **Created:** [October 6, 2002, 2:21pm UTC](https://boards.straightdope.com/t/physicists-can-you-help-settle-a-dispute/131065 "2002-10-06T14:21:27Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 7, 2002, 9:48am UTC](https://boards.straightdope.com/t/physicists-can-you-help-settle-a-dispute/131065/21 "2002-10-07T09:48:01Z")
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. ---
**Author:** ![Andy](https://avatars.discourse-cdn.com/v4/letter/a/aeb1de/32.png) [@Andy](https://boards.straightdope.com/u/Andy)\ **Post date:** [October 7, 2002, 9:54am UTC](https://boards.straightdope.com/t/physicists-can-you-help-settle-a-dispute/131065/22 "2002-10-07T09:54:43Z")
I get it, a gun like device, on some sort of vehicle which runs on tracks. Man, we could really solve this thing!!! ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 7, 2002, 10:17am UTC](https://boards.straightdope.com/t/physicists-can-you-help-settle-a-dispute/131065/23 "2002-10-07T10:17:00Z")
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. ---
**Author:** ![Eleusis](https://avatars.discourse-cdn.com/v4/letter/e/f4b2a3/32.png) [@Eleusis](https://boards.straightdope.com/u/Eleusis)\ **Post date:** [October 7, 2002, 10:32am UTC](https://boards.straightdope.com/t/physicists-can-you-help-settle-a-dispute/131065/24 "2002-10-07T10:32:42Z")
> [@](#): > > \*Originally posted by Andy \* > \*\*I get it, a gun like device, on some sort of vehicle which runs on tracks. > Man, we could really solve this thing!!! \*\* On the remote possibility that you have access to JATO rocket, might I suggest something [like this](http://216.239.35.100/search?q=cache:Et1xIRotj1gC:www.cultdeadcow.com/cDc_files/cDc-363/+&hl=en&ie=UTF-8)? (google cache, site is down right now) It’s a good read anyway if (IMHO) purely fiction. Sorry for the hijack. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [October 7, 2002, 11:38am UTC](https://boards.straightdope.com/t/physicists-can-you-help-settle-a-dispute/131065/25 "2002-10-07T11:38:16Z")
> [@](#): > > \*Originally posted by Urban Ranger \* > \*\*My initial answer is incorrect. > > However, the bullet will not drop to the ground, either. Consider the situation where the bullet is fired one meter from the end of the train. Nothing else has changed. > > Now remember that the train moves in the opposite direction of the bullet. If there’s any wind, it will be _tail_ wind. \*\* 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. ---
**Author:** ![Beastal](https://avatars.discourse-cdn.com/v4/letter/b/a183cd/32.png) [@Beastal](https://boards.straightdope.com/u/Beastal)\ **Post date:** [October 7, 2002, 1:23pm UTC](https://boards.straightdope.com/t/physicists-can-you-help-settle-a-dispute/131065/26 "2002-10-07T13:23:27Z")
Thanks guys. So the answer is, more or less, the bullet will fall straight down, from the point of view of a stationary observer. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [October 7, 2002, 1:40pm UTC](https://boards.straightdope.com/t/physicists-can-you-help-settle-a-dispute/131065/27 "2002-10-07T13:40:51Z")
Emphatically yes. [sup](More or less)[/sup] [Previous page](https://boards.straightdope.com/t/physicists-can-you-help-settle-a-dispute/131065.md?page=1)