# The Naked Scientists Forum

### Author Topic: Are falling bullets dangerous?  (Read 5753 times)

#### Connyank

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• Posts: 2
##### Are falling bullets dangerous?
« on: 07/02/2011 10:30:02 »
Frank Auer  asked the Naked Scientists:

On a recent podcast, The Naked Scientists discussed if shooting a gun straight up was dangerous due to the falling bullets. I believe it was said the bullets could be deadly. I don't know if anyone is familiar with the United Stated TV program, Myth Busters, but they did an extensive experiment that showed that the falling bullets only reach terminal velocity and would not result in injury. If the gun was shot at an angle the bullets would retain some of their initial velocity and could be dangerous.

Just wondering if you have any other thoughts on this.

What do you think?
« Last Edit: 07/02/2011 10:30:02 by _system »

#### assimilated

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##### Are falling bullets dangerous?
« Reply #1 on: 08/02/2011 14:38:44 »
I think you are correct.

I'm sure someone could calculate the terminal velocity given the height and mass/size of the bullet and taking into account friction from air.

Its a bit like a coin tossed from a high building, it will not reach sufficient velocity to do much damage.

#### imatfaal

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##### Are falling bullets dangerous?
« Reply #2 on: 08/02/2011 17:33:43 »
its a chaotic system - most of the times it will tumble, every so often the penny will tend to roll on its short axis and cut through the air.  The bullet has angular momentum (with the axis from point to tail) which has to negated somehow - otherwise it will maintain that spin and still be rifling (rather than tumbling) when it gets back to earth.  Mythbusters is great fun - and good empirical investigation, but it is not the be all and end all

#### Bored chemist

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##### Are falling bullets dangerous?
« Reply #3 on: 08/02/2011 19:54:34 »
To a reasonable approximation the bullet is a small dense sphere.
For that case, here are the equations
http://en.wikipedia.org/wiki/Stokes'_law

Knock yourselves out.

#### Eric A. Taylor

• Sr. Member
• Posts: 447
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##### Are falling bullets dangerous?
« Reply #4 on: 09/02/2011 04:40:34 »
Frank Auer  asked the Naked Scientists:

On a recent podcast, The Naked Scientists discussed if shooting a gun straight up was dangerous due to the falling bullets. I believe it was said the bullets could be deadly. I don't know if anyone is familiar with the United Stated TV program, Myth Busters, but they did an extensive experiment that showed that the falling bullets only reach terminal velocity and would not result in injury. If the gun was shot at an angle the bullets would retain some of their initial velocity and could be dangerous.

Just wondering if you have any other thoughts on this.

What do you think?

Every year several people are killed by falling bullets, especially around new years in the United States and in the Middle East. After the end of the second US/Iraq war 14 people in Baghdad were killed by falling AK bullets fired by celebrants. Myth Busters is quite a lot of fun but should be taken with quite a large grain of salt. They are movie special effects producers, not scientists. They make quite a lot of mistakes, like firing birds at light aircraft windshields, which are not rated for bird strike (They are made from 1/4 inch Plexiglas) or putting 10,000 pound thrust rockets into a car without proper mounts. If you watch the high-speed of THAT explosion (which was one of their best) you'll see the rocket motors shoot out of the front of the car just before the big boom.

#### Connyank

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• Posts: 2
##### Are falling bullets dangerous?
« Reply #5 on: 10/02/2011 02:06:16 »
I agree the falling bullet is like a coin dropped from a building, the initial velocity is not relevant after it starts to fall back, assuming it was not shot at such an angle that it still maintains some of it's initial velocity. I'm sure people are killed by "falling" bullets, but they may actually not be falling but on a trajectory.

The Myth Busters do make mistakes, but it's good that they often go back and try again when fans complain.

Thanks to everyone for the input.

#### Eric A. Taylor

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• I before E except after C, unless weird science
##### Are falling bullets dangerous?
« Reply #6 on: 10/02/2011 04:54:23 »
Indeed, But sometimes they make mistakes again, like in the rocket car myth they tested before. Take "Myth Busters" with a grain of salt, and Don't try what they do at "home".

I saw a program about a guy who discovered that if you punch a shark in it's nose it will stun it, giving you a chance to escape. They stated before showing it that it should not be tried at home. I thought, if you could do that at your home you should consider getting a new home. (Like who wants sharks IN their house?)

#### Bored chemist

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##### Are falling bullets dangerous?
« Reply #7 on: 10/02/2011 06:58:10 »
Does it work on loan sharks?
If you have sharks in your house, perhaps you should try punching them; they might swim away.

#### The Naked Scientists Forum

##### Are falling bullets dangerous?
« Reply #7 on: 10/02/2011 06:58:10 »