If you are traveling at 100 MPH and have a gun that shoots bullets at 100 MPH

[Mermaidman]

Originally posted by: SViper

Originally posted by: mooncancook
So if I'm traveling on a train at 100mph, and I throw a rock backward at 10mph, the rock is going to come back and hit me at 90mph. I'll be damned.

ROFLMAO!!! That was a good one.

I laughed till I cried. Is there an emoticon for that?

 

[torpid]

Would the bullet just stop in the chamber? I'm not sure how guns work, does it get to 100 mph only as it exits the chamber or before?

 

[HopJokey]

Originally posted by: Doboji
I think it would still move from the spot you fired it at 100mph... the distance between you and the bullet would be increasing at 200mph

I vote for this answer. If "person x" is moving North at 100mph (on a train, car, etc.) and drops an object like a rock on the ground, the rock will seem like it is moving at 100 mph south relative to person x. Now if person x shoots a bullet travelling at 100mph in the south direction from person x's point of reference it the bullet will be travelling 200 mph south.

 

[Aikouka]

Originally posted by: DT4K
2 doesn't make any sense. Yes, once the bullet is fired, the gun is irrelevant. But that's not the point. If the gun has a muzzle velocity of 100 mph and it's moving backwards at 100mph (relative to the ground), then the bullet is going to exit the gun moving at 0 mph (relative to the ground) and will indeed fall to the ground (excluding the wind effects mentioned previously)

Okay, now this is what I'm not getting here. Now you're talking all relative where I'm talking physical. Physically, the bullet doesn't magically stop just because you're moving as the only outside forces to act upon the bullet are wind and gravity (wind probably being the worse offender as we talked about the wake forming around the truck and that'd end up forcing the bullet down if you're going 100).

The only way I could see what you're talking about occurring is if the bullet is shot forward so the speeds of both objects are the same and it'd appear (relative to the truck) that the bullet is not moving once it leaves the chamber and becomes part of the relative space. Now unless I read incorrectly, this thread is about the bullet being shot backward.

 

[imported_bum]

Originally posted by: Tom

Originally posted by: animalia

Originally posted by: MercenaryForHire
Those are some slow-ass bullets.

- M4H

wait so if a major league baseball pitcher throws a baseball out that same car...it's not gonna leave the car? wtf

assuming nothing gets in the way, the ball and the car will move apart from each other at 200 mph total, so no, it wouldn't stay in the car.

but to someone not in the car, the ball would be stationary. or with gravity would see it fall straight towards the Earth.

I don't think this is correct. The bullet would appear stationary if someone was going the backwards direction at 100 mph, because they'd be alongside it, right? The fact that the gun is moving away from the bullet does not cancel the fact the bullet still has velocity.

just to clarify:
The bullet appears to be going 200 mph away from observer on the train.
The bullet appears to be going 100 mph past a stationary observer.
The bullet appears to be going 0 mph to an observer on a train going the opposite direction.

Not 100%, but this makes sense to me. Pretty sure it's right.

edit: so yeah... I'm wrong. It's been awhile since I thought about physics, guess I tried to think this through more than necesary.

 

[DeadByDawn]

If you are in a car doing the speed of light in the dark, and you turn your headlights on, will they shine in front of the car so you can see?

 

[torpid]

Originally posted by: DeadByDawn
If you are in a car doing the speed of light in the dark, and you turn your headlights on, will they shine in front of the car so you can see?

I think what would happen is that cavemen from the flintstones era would see the light because it would go back in time.

 

[ZetaEpyon]

Originally posted by: bum
I don't think this is correct. The bullet would appear stationary if someone was going the backwards direction at 100 mph, because they'd be alongside it, right? The fact that the gun is moving away from the bullet does not cancel the fact the bullet still has velocity.

just to clarify:
The bullet appears to be going 200 mph away from observer on the train.
The bullet appears to be going 100 mph past a stationary observer.
The bullet appears to be going 0 mph to an observer on a train going the opposite direction.

Not 100%, but this makes sense to me. Pretty sure it's right.

It's not right.

You are neglecting the fact that the bullet has a velocity of 100mph even before it's shot from the gun.

Since you are presumably facing backwards to shoot the gun, we'll say that you (and the gun and bullet) are moving at -100mph to start with. Fire the bullet, and it's moving at 100mph away from you. However, it was already moving at -100mph. Add this to its velocity relative to you, and you find that it does indeed just drop relative to the ground.

-100mph + 100mph = 0 mph

This means it's moving away from you at 100mph.
It is falling straight down to an observer on the ground.
It appears to be moving at 100mph away from an observer on a train moving the other direction.

 

[foghorn67]

Originally posted by: mooncancook
So if I'm traveling on a train at 100mph, and I throw a rock backward at 10mph, the rock is going to come back and hit me at 90mph. I'll be damned.

LOL.

/ass hedplodes.

 

[hanoverphist]

Originally posted by: GuitarDaddy
Pie r round
Cornbread r square

cornbread muffins are round

 

[Stuxnet]

You bought a POS gun, my friend.

 

[funboy6942]

It would actually travel back in time.

 

[Born2bwire]

Originally posted by: torpid
Would the bullet just stop in the chamber? I'm not sure how guns work, does it get to 100 mph only as it exits the chamber or before?

Technically, it would be accelerated along the barrel until it exited the muzzle of the rifle and here we are assuming the muzzle velocity is 100 mph. From the frame of reference of the shooter, the bullet will still travel out at 100 mph, only from those that are at rest on the ground will the bullet have no horizontal velocity. Basically, from the ground reference, I would picture the bullet moving along in the barrel with the car and when fired, slowly decellerating up to a standstill when it leaves the barrel.

 

[foghorn67]

Originally posted by: hanoverphist

Originally posted by: GuitarDaddy
Pie r round
Cornbread r square

cornbread muffins are round

Pies at McDonalds are rectangle. Sqaure's older cousin.

 

[Q]

I don't think it would drop straight down, it would immediately have no velocity then the wind would carry it

 

[theprodigalrebel]

Threads like these make me doubt my admittedly average understanding of physics more than I should.

 

[LeiZaK]

The bullet would go back in time to kill you when you woke up this morning.

 

[hanoverphist]

Originally posted by: bum

I don't think this is correct. The bullet would appear stationary if someone was going the backwards direction at 100 mph, because they'd be alongside it, right? The fact that the gun is moving away from the bullet does not cancel the fact the bullet still has velocity.

just to clarify:
The bullet appears to be going 200 mph away from observer on the train.
The bullet appears to be going 100 mph past a stationary observer.
The bullet appears to be going 0 mph to an observer on a train going the opposite direction.

Not 100%, but this makes sense to me. Pretty sure it's right.

you said what i was thinking

 

[cvstrat]

There really isn't any room for speculation in this. It's pretty simple.

All other variables ignored the bullet drops straight to the ground. Makes no difference where you stand (on the train or the ground) it drops right to the ground (if it even leaves the barrel of the gun at all)

Imagine if the train car was stationary. You throw the ball 100mph it slams into the back wall at 100mph.

Imagine the train is moving 100mph the opposite direction. The wall slams into the ball at 100mph. The ball is stationary once it leaves your hand and ignoring gravity would float there until the back of the train slams into it.

aka it stops, and w/gravity it falls right to the ground.

 

[cvstrat]

Originally posted by: hanoverphist

Originally posted by: bum

I don't think this is correct. The bullet would appear stationary if someone was going the backwards direction at 100 mph, because they'd be alongside it, right? The fact that the gun is moving away from the bullet does not cancel the fact the bullet still has velocity.

just to clarify:
The bullet appears to be going 200 mph away from observer on the train.
The bullet appears to be going 100 mph past a stationary observer.
The bullet appears to be going 0 mph to an observer on a train going the opposite direction.

Not 100%, but this makes sense to me. Pretty sure it's right.

you said what i was thinking

Incorrect:

The bullet appears to be going 100mph away from the observer on the trian.
The bullet appears to be giong 0mph (falls to the ground) to a stationary observer.
The bullet apperas to be going 100mph away from the observer on a train going the opposite direction.

Edit: your scenario would be correct if the person on the train going the opposite direction dropped the bullet to the ground

 

[DT4K]

The lack of basic physics knowledge(or even common sense) on this forum is quite stunning.

NO, it will NOT appear to be going 200mph from the perspective of the shooter. The gun has a muzzle velocity of 100 mph. It's not going to double just because you are moving backwards. The bullet will appear to be going 100 mph from the perspective of the shooter, which means it's going 0 mph from the perspective of the ground. It's really as simple as:

100 + (-100) = 0

 

[randay]

Originally posted by: cvstrat

Originally posted by: hanoverphist

Originally posted by: bum

I don't think this is correct. The bullet would appear stationary if someone was going the backwards direction at 100 mph, because they'd be alongside it, right? The fact that the gun is moving away from the bullet does not cancel the fact the bullet still has velocity.

just to clarify:
The bullet appears to be going 200 mph away from observer on the train.
The bullet appears to be going 100 mph past a stationary observer.
The bullet appears to be going 0 mph to an observer on a train going the opposite direction.

Not 100%, but this makes sense to me. Pretty sure it's right.

you said what i was thinking

Incorrect:

The bullet appears to be going 100mph away from the observer on the trian.
The bullet appears to be giong 0mph (falls to the ground) to a stationary observer.
The bullet apperas to be going 100mph away from the observer on a train going the opposite direction.

Edit: your scenario would be correct if the person on the train going the opposite direction dropped the bullet to the ground

yes but how long does train A take to reach chicago?

 

[yosuke188]

Originally posted by: randay

Originally posted by: cvstrat

Originally posted by: hanoverphist

Originally posted by: bum

I don't think this is correct. The bullet would appear stationary if someone was going the backwards direction at 100 mph, because they'd be alongside it, right? The fact that the gun is moving away from the bullet does not cancel the fact the bullet still has velocity.

just to clarify:
The bullet appears to be going 200 mph away from observer on the train.
The bullet appears to be going 100 mph past a stationary observer.
The bullet appears to be going 0 mph to an observer on a train going the opposite direction.

Not 100%, but this makes sense to me. Pretty sure it's right.

you said what i was thinking

Incorrect:

The bullet appears to be going 100mph away from the observer on the trian.
The bullet appears to be giong 0mph (falls to the ground) to a stationary observer.
The bullet apperas to be going 100mph away from the observer on a train going the opposite direction.

Edit: your scenario would be correct if the person on the train going the opposite direction dropped the bullet to the ground

yes but how long does train A take to reach chicago?

Assuming that the tunnel is .52 miles and the train itself is .52 hectometer, it would take 542 minutes to reach China.

 

[Schfifty Five]

bullet = 0 mph to a stationary observer on the ground
bullet = 100mph to a person on the car/train

 

[Whisper]

Originally posted by: Doboji
I think it would still move from the spot you fired it at 100mph... the distance between you and the bullet would be increasing at 200mph

Edit: I successfully confused myself, and have no idea what's going on. Yeehaw.

Ok, maybe I was actually right, and the bullet would appear to be going 100mph, not 200mph, away from an observer on the train. But I'm still confusing myself.