Speed of a bullet and gravity? Any budding forensic scientists out there?

[Michael52]

Interesting story here that gave rise to this question.

http://uk.news.yahoo....y-bullet-1a5e080.html

How high up can a bullet go and what kind of speeds would it need to be able to enter a humans skull? Im sure that because of the light weight it couldn't enter.

Something similar was done on the Mythbusters programme called "Penny Drop" when they tested the theory whether a penny dropped from the Empire state building could kill you. These were the results.

A penny dropped from a skyscraper lands with enough force to either kill a pedestrian on the sidewalk below or embed itself into the sidewalk.

Firing a penny at terminal velocity (65 miles per hour (105 km/h)) into concrete and asphalt disks and a ballistics gel head with a human skull failed to result in any penetrations, likely because the speed is too low and a penny's mass too small. Even when fired from a rifle, the penny was unable to penetrate concrete or a ballistic gel dummy's skull. Even modifying a rifle to shoot a penny at supersonic speeds failed to cause a penetration. In comparison, a real 6.5mm bullet split the dummy skull. Visiting the Empire State Building, the likely source of the myth, they realize that updrafts and roofs of lower floors would prevent a thrown penny from reaching street level.

So this may have been an accident but I think unlikely it went up and then entered his head on its decent. Any thoughts?

[ABerrant]

Mythbusters also tested "Can a bullet fired straight up in the air kill someone on the way back down?" in episode 50.

[ABerrant]

http://community.disc...01967776/m/3531991398

[jomifl]

I recall reading several news items reporting people being killed by bullets descending after joyful middle east wedding celebrations. Of course they might not have been shot straight up.

[ChuckFickens]

Asking how high up can a bullet go is like asking how fast a car can go it varies hugely

Handguns have a range that varies from about 1500m (colt45) upto anything around 3500meters (.223)..... rifle rounds can and will go a lot further than handgun rounds (upto about 5000m without getting into long rage sniper stuff)

There have been a lot of reported cases of people being killed by falling bullets though, it's the reason that the firing of guns is prohibited inside of all US city limits, except for at licensed gun ranges.

[wildwood]

You need to take the Mythbuster's results with a grain of salt. A penny does not have a terminal velocity of 105kph. It tumbles on the way down and decelerates when the flat sides are in the horizontal plane and increases when the edges are.

What is the actual question? The speed and terminal velocity of a falling bullet can not be calculated until we know the calibre, shape, type and horizontal projection.

The bullet in the man's head has only entered the soft tissue, so is likely to have been fired some distance away and while descending entered the skin at an unknown angle.

[waterboatman]

a .22 bullet can most certainly enter the scull. On a low pressure day some types can go supersonic.

[Michael52]

Thanks for the answers everyone i was just trying to understand this weird phenomenon.
Interestingly this X-ray shows that the bullet was at the back of his head which tells me that the gun was fired horizontally or at an angle into the air and not straight up.

http://www.telegraph....y-25-August-2010.html

[Michael52]

Unless he was sprawled on the pavement facedown^ Which could've been the case as he said he was so drunk he didn't realize but unlikely.