Drop a bullet vs. Shoot a bullet

[vrbaba]

cant believe theres is 5 page discussion on it.
where are yall's high school physics memory?
so unexpected of AT....well, just proves the great diversity of people posting here

 

[Electric Amish]

Originally posted by: LordMorpheus

Originally posted by: RaynorWolfcastle

Originally posted by: Kyteland
The dropped one. Since the earth is a sphere, and not flat, the fired bullet will actually have farther to fall than the dropped one.

Note that this assumes that it is fired in a vacuum.

LOL, you want to ignore air resistance and the fact that terrain isn't flat but you want to take into account the fact that the Earth's surface is curved?

You must be a mathematician or a physicist

You can't shoot a firearm in a vacuum!!!!!!

Sure, you just had to bring THAT up!

 

[akubi]

Originally posted by: EyeMWing
But in a physics world, we don't have curvature. Or terrain. Or an atmosphere.)

Originally posted by: Electric Amish
Applying the Physicist's favorite conditions (vacuum, infinitely flat surface, constant gravity, etc)

only in high school kids!

 

[91TTZ]

Originally posted by: Electric Amish

4. However, if you shot the bullet at 17,500 miles per hour, the bullet would never touch the ground, since its rate of descent will match the curvature of the Earth. It would always be "falling" and never hit the ground, since the ground it's vertically falling towards is constantly curving away from it, due to the horizontal speed.

This is assuming the bullet maintains it's speed, which it will not.

Applying the Physicist's favorite conditions (vacuum, infinitely flat surface, constant gravity, etc) they would hit at the same time.

Real world, the dropped bullet would hit first.

When I answered that, the assumptions that everyone was working under were normal curved Earth, normal gravity, no air resistance.

 

[Literati]

Originally posted by: vrbaba
cant believe theres is 5 page discussion on it.
where are yall's high school physics memory?
so unexpected of AT....well, just proves the great diversity of people posting here

We were to busy having sex and being cool to remember this not relevant in the real working world crap... nerd!

 

[91TTZ]

Originally posted by: LordMorpheus

You can't shoot a firearm in a vacuum!!!!!!

Wrong. Yes you can. Give a gun to an astronaut.

 

[glugglug]

Dropped bullet will hit the ground long before the fired one.
The tiny bit of air resistance the dropped bullet experiences will spin it until it is pointed upwards, leaving a small profile parallel to the ground.
The fired bullet will remain pointed horizontally (also due to air resistance), giving it a larger profile parallel to the ground, and also will have a lot more drag from the air it is moving through preventing it from falling quickly.

 

[TankGuys]

Originally posted by: Kyteland

That's only true if you ignore a lot of things, like the curvature of the earth. The question didn't state "There are two point sources on a frictionless plane, one dropped and one fired from 4 feet."

So for whom is Newton spinning?

Okay, let's re-phrase the answer:

If the question is taking into account ALL possible angles, air resistance, earth curvature, the gun "kicking back" and thus actually shooting the bullet ever-so-slightly upwards, etc etc, then yes, the fired bullet hits a few fractions of a second after the dropped one.

If the question is asking if a dropped bullet will fall 4 feet faster than a fired bullet will fall 4 feet, the answer is they hit at the same time.

That pretty much sums it up

 

[91TTZ]

I already answered the real world question. The dropped bullet would hit first. The curvature of the Earth is not much, but it isn't negligible, either.

In the real world, from a mathematical standpoint, the shot bullet would have to fall slightly farther due to the curvature of the Earth.

/thread.

 

[LordMorpheus]

Originally posted by: 91TTZ

Originally posted by: LordMorpheus

You can't shoot a firearm in a vacuum!!!!!!

Wrong. Yes you can. Give a gun to an astronaut.

no, you can't. A gun works by creating a spark that ignites the gunpowder . . . the sudden expansion due to the burning poweder pushes the bullet out of the barrel . . .

However, gunpowder won't burn unless there is oxygen available for the reaction. Go on, take a gun into space and pull the trigger. You'll get nothing.

 

[91TTZ]

Originally posted by: LordMorpheus


no, you can't. A gun works by creating a spark that ignites the gunpowder . . . the sudden expansion due to the burning poweder pushes the bullet out of the barrel . . .

However, gunpowder won't burn unless there is oxygen available for the reaction. Go on, take a gun into space and pull the trigger. You'll get nothing.

Dead wrong.

Gunpowder doesn't need oxygen, as it's comprised of both the fuel AND oxidizer.


You can fire a gun anywhere. In space, under water, etc.

 

[Armitage]

Originally posted by: 91TTZ
Ok, here it is.

You drop a bullet from 4 feet up. It falls straight down, takes 0.4988 seconds to hit (link)

You fire a bullet from 4 feet up. Typical round at 3,000 feet/second. At the end of .4988 seconds when the other bullet hit the ground, the bullet fired from the rifle has travelled 1496.4 feet in the horizontal direction. Due to the curvature of the Earth, the Earth's surface drops 1 foot every 6499.23 feet.

Therefore, at the time that the dropped bullet hits the ground, the rifle bullet will be 1496.4 feet away and will NOT have hit the ground yet, since it must fall another 0.23 feet, which is about 2.76 inches.

So there you have it. When the dropped bullet hits the ground, the fired bullet will still have 2.76 inches left to fall, due to the horizontal distance it covered and the curvature of the Earth.

:thumbsup:
Looks about right to me.

I'm not sure which is scarier about this thread - the dismal state of reading comprehension or the dismal state of science education

 

[akubi]

Originally posted by: LordMorpheus

Originally posted by: 91TTZ

Originally posted by: LordMorpheus

You can't shoot a firearm in a vacuum!!!!!!

Wrong. Yes you can. Give a gun to an astronaut.

no, you can't. A gun works by creating a spark that ignites the gunpowder . . . the sudden expansion due to the burning poweder pushes the bullet out of the barrel . . .

However, gunpowder won't burn unless there is oxygen available for the reaction. Go on, take a gun into space and pull the trigger. You'll get nothing.

wrong, this is a common misconception.

gunpowder, unlike wood, etc can ignite in a vacuum.
robert hooke discovered this in the late 1600s.

 

[Rock Hydra]

Originally posted by: hypn0tik

Originally posted by: Rock Hydra

Originally posted by: Saulbadguy
Which way is the gun pointed?

At first I was assuming that the gun was pointed downward, since the OP didn't state otherwise.

Uhhhh, perhaps you should read the OP fully??

 

[FrustratedUser]

Originally posted by: gigapet
barring no air resistance and gravity remains constant they hit the ground at the exact same time.

 

[Cerpin Taxt]

Originally posted by: 91TTZ

Originally posted by: LordMorpheus

You can't shoot a firearm in a vacuum!!!!!!

Wrong. Yes you can. Give a gun to an astronaut.

Space vessels do not harbor vacuums inside them. Astronauts do not live in vacuums while in space. In fact, a "true vacuum" cannot exist in reality at all.

-Garth

 

[mchammer187]

Originally posted by: 91TTZ

Originally posted by: LordMorpheus


no, you can't. A gun works by creating a spark that ignites the gunpowder . . . the sudden expansion due to the burning poweder pushes the bullet out of the barrel . . .

However, gunpowder won't burn unless there is oxygen available for the reaction. Go on, take a gun into space and pull the trigger. You'll get nothing.

Dead wrong.

Gunpowder doesn't need oxygen, as it's comprised of both the fuel AND oxidizer.

we are not talking about zero gravity we are talking about a vacuum which relies on the expansion of gases in the chamber to propel the bullet forward

if there is no gases to expand there is no propulsion

this is the reason why you can't shoot guns underwater or why you cant start a fire underwater

 

[91TTZ]

Originally posted by: Garth

Space vessels do not harbor vacuums inside them. Astronauts do not live in vacuums while in space. In fact, a "true vacuum" cannot exist in reality at all.

-Garth

I didn't say "inside a spacecraft".

Give it to this guy. Put it in his glove and let him fire it.

 

[91TTZ]

Originally posted by: mchammer187

we are not talking about zero gravity we are talking about a vacuum which relies on the expansion of gases in the chamber to propel the bullet forward

if there is no gases to expand there is no propulsion

this is the reason why you can't shoot guns underwater or why you cant start a fire underwater

Wrong, DEAD WRONG.

A gun CAN shoot out in space, and it CAN shoot under water. This is common knowledge to those who are not uneducated 15 year olds.

Gunpowder contains BOTH the fuel AND the oxidizer, and does not depend on outside oxygen for its reaction. This is one of the BASICS of chemistry.

Would the unknowledgeable people PLEASE leave this thread? You are spouting complete nonsense.

 

[MrDudeMan]

ok here it is. this is assuming no curvature of the earth, its in a vacuum, and there is no wind resistance. if you factor in the curvature of the earth, these results change and the dropped bullet hits first. i could do those calculations but at this point in time i am too lazy.

Text

metric is easier to use in calculations, but you get the idea.

 

[Cerpin Taxt]

Originally posted by: 91TTZ

Originally posted by: Garth

Space vessels do not harbor vacuums inside them. Astronauts do not live in vacuums while in space. In fact, a "true vacuum" cannot exist in reality at all.

-Garth

I didn't say "inside a spacecraft".

Yes, you're right. I misunderstood what you were saying.

-Garth

 

[Armitage]

Originally posted by: mchammer187

Originally posted by: 91TTZ

Originally posted by: LordMorpheus


no, you can't. A gun works by creating a spark that ignites the gunpowder . . . the sudden expansion due to the burning poweder pushes the bullet out of the barrel . . .

However, gunpowder won't burn unless there is oxygen available for the reaction. Go on, take a gun into space and pull the trigger. You'll get nothing.

Dead wrong.

Gunpowder doesn't need oxygen, as it's comprised of both the fuel AND oxidizer.

we are not talking about zero gravity we are talking about a vacuum which relies on the expansion of gases in the chamber to propel the bullet forward

if there is no gases to expand there is no propulsion

The gases are created by the explosion of the gunpowder. Which, as others have pointed out, can burn in a vacuum because it contains it's own oxidizer.

this is the reason why you can't shoot guns underwater or why you cant start a fire underwater

You can very well fire a gun underwater as long as the powder stays dry.

 

[MrDudeMan]

Originally posted by: 91TTZ

Originally posted by: mchammer187

we are not talking about zero gravity we are talking about a vacuum which relies on the expansion of gases in the chamber to propel the bullet forward

if there is no gases to expand there is no propulsion

this is the reason why you can't shoot guns underwater or why you cant start a fire underwater

Would the unknowledgeable people PLEASE leave this thread? You are spouting complete nonsense.

WRONG.

A gun CAN shoot out in space, and it CAN shoot under water. This is common knowledge to those who are not uneducated 15 year olds.

yeah these fools are spreading pure crap. a gun can definitely be fired in space. if you dont know that or cant grasp that concept you are a complete and utter moron. the gases that expand out of the barrel come from the fuel that has been burned by the ignition of the powder.

 

[neutralizer]

Some people really need to go back and take physics.

 

[rahvin]

Originally posted by: 91TTZ
Would the unknowledgeable people PLEASE leave this thread? You are spouting complete nonsense.

You are asking a lot! Just take it for what it is, humor!