If you fired a bullet in a desert...

[SkyBlueFlux]

The earth surface is curved, irrespective of altitude. A shot fired horizontally is actually fired at a tangent to the curved surface. The distance the fired bullet has to fall is slightly greater than the original height because of this and therefore it takes slightly longer to reach the surface. The dropped bullet lands first.

The Earth is sufficiently flat for that to not be the case for most weapons though. Espcially when firing indoors on a flat surface, a la:

[youtube]http://www.youtube.com/watch?v=D9wQVIEdKh8[/youtube]

Although admittedly I haven't watched the above clip yet, I've actually just taken the time to calculate myself how much of a difference the curvature of the Earth would generally make (anything to get away from exam revision) and although it would obviously vary I've come up with the following:

If the bullet were to drop from rest for approximately one whole second, it would generally fall about 4.9m (ignoring air resistance).

So let's say you start from a position which is 4.9m off the ground. The bullet travels at a standard 680mph horizontally, then the difference in the height dropped by the horizontal travelling bullet and the stationary dropped bullet, solely due to the curvature of the Earth, is roughly 8mm.

That extra 8mm would prolong the free-fall by approximately 0.0028s or 2.8ms.

This is with a gun fired at a height off the ground which is twice your average man's height.

The thing is, as with all physics, it's about how well these things can be approximated to a real system. In reality there's a fuckton of stuff out there which can effect the way these bullets travel. Air currents, the rotation of the earth, hell, even the malleability of the metal that the bullet is made from will have some kind of effect. You can't take them all into account as that would take forever.

For all intents, the two bullets will land nearly at exactly same time and for most practical purposes you can say that with confidence.

 

[BimboBob]

Thanks, you're only 2 years late.

Surely the height of the building matters. 20 foot up the gun fired bullet will hit the ground first.

It doesn't matter how high up the bullet is fired from, as long as it is fired horizontally, and the bullet dropped is dropped from the same height as the gun was fired.

Edit: I think we discussed this in here. If we fired the bullet fast enough this would not be case, due to the curvature of earth. Same thing if we fired from very high up.

Sorry, missed the horizontal bit. I thought it was a bit weird...

 

[goat boy]

Extra credit:

Say our hypothetical bullet that is capable of travelling exactly the circumference of the planet abd hitting us in the back if the head is made of standard lead/ brass etc. Would the air friction cause the temperature of the missile to rise above its melting point? is there an alternative metal compound that might be a better material from which to make our hypothetical round?

 

[BulgarianPride]

I think this experiment is a lot more interesting if the bullet is shot at relativistic speeds. Say we are on infinitely flat planet that has the same gravity as ours. We fire the gun horizontally, the bullet moving at 35% of speed of light. What would land first, shell or bullet? What would the bullet "see" happen, and what would the shell "see" happen?

 

[Pigeonho]

Bump: (was an interesting thread, this).

I remembered this thread in the middle of the night when I was reading the Sky News app. The Russian soldiers firing bullets upwards and over the Ukrainian lot. 'So', I thought, 'Where the fuck are those bullet's going to land then?'.
What goes up, must come down, after all.

It's like when those lot in Iraq go bonkers and start firing their guns into the air in celebration. Surely it rains bullets moments later?

 

[BlueHammer85]

Bump: (was an interesting thread, this).

I remembered this thread in the middle of the night when I was reading the Sky News app. The Russian soldiers firing bullets upwards and over the Ukrainian lot. 'So', I thought, 'Where the fuck are those bullet's going to land then?'.
What goes up, must come down, after all.

It's like when those lot in Iraq go bonkers and start firing their guns into the air in celebration. Surely it rains bullets moments later?

A surprising amount of people get killed because of this, Most major cities have laws in place to try to keep people from shooting guns into the air in celebration.

- Three people in the Philippines died due to stray bullets fired to welcome the arrival of the new year 2011.

- In 2010 a Turkish bridegroom killed three relatives when he fired an AK-47 at his own wedding. In the same year, Jordan's King Abdullah II ordered his country's authorities to clamp down on the practice after two people were killed and 13 more injured in one incident.
Continue reading the main story
The Answer

- When the Iraqi football team defeated Vietnam in 2007's Asia Cup, three people were killed in Baghdad amid widespread gunshots as fans celebrated. Celebratory gunfire in Kuwait after the end of the Gulf War in 1991 was blamed for 20 deaths


According to a 1962 study, .30 calibre rounds can reach terminal velocities of 300 feet (91m) per second as they fall. More recent research has indicated that 200 feet (61m) per second is enough to penetrate the skull.

 

[aguero93:20]

Bump: (was an interesting thread, this).

I remembered this thread in the middle of the night when I was reading the Sky News app. The Russian soldiers firing bullets upwards and over the Ukrainian lot. 'So', I thought, 'Where the fuck are those bullet's going to land then?'.
What goes up, must come down, after all.

It's like when those lot in Iraq go bonkers and start firing their guns into the air in celebration. Surely it rains bullets moments later?

A surprising amount of people get killed because of this, Most major cities have laws in place to try to keep people from shooting guns into the air in celebration.

- Three people in the Philippines died due to stray bullets fired to welcome the arrival of the new year 2011.

- In 2010 a Turkish bridegroom killed three relatives when he fired an AK-47 at his own wedding. In the same year, Jordan's King Abdullah II ordered his country's authorities to clamp down on the practice after two people were killed and 13 more injured in one incident.
Continue reading the main story
The Answer

- When the Iraqi football team defeated Vietnam in 2007's Asia Cup, three people were killed in Baghdad amid widespread gunshots as fans celebrated. Celebratory gunfire in Kuwait after the end of the Gulf War in 1991 was blamed for 20 deaths


According to a 1962 study, .30 calibre rounds can reach terminal velocities of 300 feet (91m) per second as they fall. More recent research has indicated that 200 feet (61m) per second is enough to penetrate the skull.

We were talking about this a while back, imagine how dangerous it would be if you were to fire shotgun cartridges into the air, they might not reach the same velocity on the way down but they'd have 20-40 times as much chance of hitting somebody when they did fall.

 

[Blue Mist]

Ok Ok accepting all of the previously posts as being accurate Has Phil Jones's penalty come back down yet ?



Just askin'

 

[west didsblue]

Bump: (was an interesting thread, this).

I remembered this thread in the middle of the night when I was reading the Sky News app. The Russian soldiers firing bullets upwards and over the Ukrainian lot. 'So', I thought, 'Where the fuck are those bullet's going to land then?'.
What goes up, must come down, after all.

It's like when those lot in Iraq go bonkers and start firing their guns into the air in celebration. Surely it rains bullets moments later?

Correct, they will all hit the ground after a few seconds but will have lost most of their speed due to air resistance so if it hit you, it might hurt but wouldn't kill you.

The energy in a bullet is proportional to the square of the velocity. An AK-47 muzzle velocity is about 700 m/s. The terminal velocity on its way down due to air resistance would be about 20 m/s so a bullet would have lost 99.9% of its energy by the time it hits the ground.

 

[aguero93:20]

Ok Ok accepting all of the previously posts as being accurate Has Phil Jones's penalty come back down yet ?



Just askin'

No but when it does RVP might want to be very fucking careful :)