If I fired a gun with a velocity of 600ft per second?

Question

From the back of a train travelling at 600 ft/sec. would the bullet just fall to earth.

Clue Think of the doppler effect

Answer 1

You are exactly correct. I don't know why so many people are getting this incorrect. It all has to do with relative motion, specifically relative velocity. Specifically, the velocity of the bullet is equal to the velocity of the train plus the velocity of the bullet with respect to the train. Mathematically, the formula for it's horizontal velocity with respect to the ground is written as:

V(b) = V(t) + V(b/a),

where the parentheses are subscripts meaning "bullet," "train," and "bullet with respect to the train," respectively.

So... let's say you are on a train traveling east, and we'll define east to be the positive direction. Therefore, you are shooting it to the west, which is exactly the negative direction:

V(b) = (600 ft/s) + (-600 ft/s)
V(b) = (600 - 600) ft/s
V(b) = 0

Therefore, no horizontal motion with respect to the ground implies that it will indeed just fall down to the earth.

Answer 2

Easy question! Forget momentum. The bullet would drop to the floor.
Speed on leaving the barrel is 600ft/sec in the train's frame of reference. Reverting to a "static" (earth) frame of reference reduces the velocity to zero. (except for the downward part obviously!)

Answer 3

I will suppose you are firing backward, (-) down the tracks and not forward, (+) up the tracks at the irate conductor who is coming to confiscate your gun. The velocity of the train is not the issue; the velocity of the bullet in reference to the tracks is the issue. Before the gun was fired the bullet had a velocity up the tracks of +600fps. When the gun (also going +600fps) was fired the bullet would have a velocity of - 600 fps relative to the gun and zero relative to the tracks.
Kerplunk !

Answer 4

No, It will keep on moving at a velocity of 600 ft/sec but it's velocity relative to your train will be 1200 ft/sec.

Answer 5

The bullet would leave the gun at 600ft/sec but would appear to be moving at 1200ft/sec because the gun is travelling away from the bullet at 600ft/sec and vice versa. I think!!!!!

Answer 6

Great thinking - i like your style.
From that i would always make sure that i travelled on very fast trains - and sat at the back. Of course, the only problem then is that i'd be travelling in the opposite direction to the bullet.......mmmmm, where is Einstein when you need him?

Answer 7

yes