Great FACT.

[fork me]

It's the same as the whole 'If a brick and feather are dropped from a height in a vacuum, they fall at the same speed' thing.

Or a ball bearing:

Or a hammer, a much more impressive demonstration:

 

[Jello]

Sure Mythbusters did a piece on this and in theory they hit Earth at same time but in practice air resistance and curvature of the earth come into play. Though they didn't use a sniper rifle the theory is the same for any gun.

 

[Sergei's Celebration]

Now I am confused I thought the original statement suggested that one bullet was fired. Therefore has a propellant charge. The second bullet droped will not hit the ground at the same time. Unless the bullet is fired on the horizontal plane and the bullet droped is on the vertical, then the factors are how close to the firing of the bullet is the second dropped. Unless I have misunderstood this thread then I appologise.

 

[Seagull27]

Now I am confused I thought the original statement suggested that one bullet was fired. Therefore has a propellant charge. The second bullet droped will not hit the ground at the same time. Unless the bullet is fired on the horizontal plane and the bullet droped is on the vertical, then the factors are how close to the firing of the bullet is the second dropped. Unless I have misunderstood this thread then I appologise.

The propellant charge is acting horizontally and therefore has no bearing on the vertical component of velocity. They both travel downwards towards the earth at the same velocity.

 

[DTES]

Unless the bullet is fired on the horizontal plane and the bullet droped is on the vertical, then the factors are how close to the firing of the bullet is the second dropped. Unless I have misunderstood this thread then I appologise.

This is the key assumption - the bullet that is fired is fired perfectly horizontally, parallel to the ground.

Perhaps easier to visualise if you were directly behind them both - aside from looking smaller as it gets further away, it isn't moving to the left or the right, so you'll see them both move towards the earth as if they were right next to each other...

Mind you, I haven't seen a thread go round and round in circles so many times...

 

[BHseagull]

Basically if you drop the bullet from the highest point the bullet shot from the gun reaches, they will hit the ground at the same time.

- If you shoot it into the air & it travels 100m up, you need to drop the bullet from 100m up when the bullet reaches that point, not the height of the gun when it fires.

- If you fire horizontally, you drop it at the same time as it is already at it's highest point.

- If you fire at your feet, you're just stupid.

 

[Waynflete]

Oh my god, I've just read through this thread and there is a lot of circular argument going on.

To clarify the OP's original statement:

If you are in a vaccuum on a perfectly flat surface and you fire a bullet perfectly horizontally and simultaneously drop a second bullet (or anything else for that matter) then they will hit the ground at the same time because gravity acts on both items equally regardless of horizontal motion. FACT!

 

[DTES]

Oh my god, I've just read through this thread and there is a lot of circular argument going on.

To clarify the OP's original statement:

If you are in a vaccuum on a perfectly flat surface and you fire a bullet perfectly horizontally and simultaneously drop a second bullet (or anything else for that matter) then they will hit the ground at the same time because gravity acts on both items equally regardless of horizontal motion. FACT!

Why does the vacuum make a difference? Surely, on the same basis as the rest of the motion, the vertical portion of the drag is the same on both bullets?

 

[Spanish Seagulls]

This is exactly why God made the internet.

 

[Waynflete]

Why does the vacuum make a difference? Surely, on the same basis as the rest of the motion, the vertical portion of the drag is the same on both bullets?

Well I'm not a physicist, but I'm guessing that a bullet-shaped object flying horizontally through the air will be acted upon in some way by air resistance/turbulence/friction that may potentially be different from the effects of the air on a bullet that's just dropped. I'm guessing that those differences may potentially affect whether each bullet falls vertically more quickly or more slowly.

I agree it's unlikely to make much difference, but stating that it's in a vacuum eliminates this variable. Another (more complicated) way to eliminate this variable I guess would be to state that the bullet is flawlessly-shaped and is fired from the gun without any spin or other force that could alter its perfectly horizontal trajectory. Also, the air itself would have to be completely still, evenly distributed, same temperature throughout etc...

 

[Simon Morgan]

The pitch and tone of Brian Blessed's voice even at a low colume causes fatal internal hemorrhaging in most types of marsupial. It is for this reason that Blessed is discouraged, if not actively barred, from entering Australia.

FACTOID.

 

[DTES]

Well I'm not a physicist, but I'm guessing that a bullet-shaped object flying horizontally through the air will be acted upon in some way by air resistance/turbulence/friction that may potentially be different from the effects of the air on a bullet that's just dropped. I'm guessing that those differences may potentially affect whether each bullet falls vertically more quickly or more slowly.

I agree it's unlikely to make much difference, but stating that it's in a vacuum eliminates this variable. Another (more complicated) way to eliminate this variable I guess would be to state that the bullet is flawlessly-shaped and is fired from the gun without any spin or other force that could alter its perfectly horizontal trajectory. Also, the air itself would have to be completely still, evenly distributed, same temperature throughout etc...

I understand what you're saying, but I still think the air resistance (still assuming it's fired perfectly horizontally) can be split into two components - one horizontal, acting against its forward motion, and one vertical, acting against the gravitational force pulling it to Earth - and so it doesn't matter. I may of course be wrong too... Who knows...?

 

[Stat Brother]

Todays podcast was all about the science of fear, I don't remember any FACTS from that.

 

[Waynflete]

I understand what you're saying, but I still think the air resistance (still assuming it's fired perfectly horizontally) can be split into two components - one horizontal, acting against its forward motion, and one vertical, acting against the gravitational force pulling it to Earth - and so it doesn't matter. I may of course be wrong too... Who knows...?

You may be right! I guess that in an extreme example, though, if a bullet was mis-shaped in such a way that it gained vertical uplift whilst travelling through the air, like an aeroplane wing, then its forward motion would influence its vertical motion. If it was in a vacuum then clearly that wouldn't be possible. Who knows?! Interesting, though