What is the PSI threshold of the human skull
hp...@gte.net
force trauma - shockwave transmits through skull, bouncing brain
against other side of skull - blunt force trauma - dead.
Considering that I easily fall at ~150mph when I skydive, which is
220fps, and a bullet w/ a much more aerodynamic shape and less surface
area to provide resistance, will easily fall faster - much faster.
And the amount of pressure exerted is determined by the amount of area
it is going over will also vary - I.E. if it is exerted on a point,
the pressure approaches infinity.
So...my point is that a majority of the time, a falling bullet hitting
someone in the head WILL kill them.
"Chris Bereznay" <br...@bigfoot.com> wrote:
>I'm tired of the "Falling Bullet's lethal?" thread. All I want to know is,
>how many pounds per square inch can the human skull take before it is
>pierced? If someone out there says the terminal velocity of a bullet is
>150f p/s then what force would this exert on a human skull, and likewise
>what is the threshold of force upon the human skull before it can be
>penetrated by a falling object.
>
Chris Bereznay
James Hallows
James
John Fuesting
pressure to snap your neck. Not the head, but oh well.
James Hallows wrote in message <35b8c7a2...@news.globalnet.co.uk>...
Mark A. Evans
casualties will result from shrapnel or debris traveling
at a velocity of 75 feet per second or greater. As far as popping
someone's skull, I'm not sure, but i DO recomend wearing a
helmet if you're entering a "falling bullet" zone :-)
Laters!
Mark
Russell Stewart
>A bullet doesn't have to penetrate to kill you - it is called blunt
>force trauma - shockwave transmits through skull, bouncing brain
>against other side of skull - blunt force trauma - dead.
>
>Considering that I easily fall at ~150mph when I skydive, which is
>220fps, and a bullet w/ a much more aerodynamic shape and less surface
>area to provide resistance, will easily fall faster -
Not necessarily. True it has less surface area and a more aerodynamic
shape, but it's also several thousand times less massive than you are.
So far, the only viable data I've seen posted to this thread indicates that
a bullet wouldn't have a terminal velocity of more than 60-70 mph. Of course,
I could be completely wrong on that, but I'd like to see some data one way
or the other.
Russell Stewart
Undergraduate
UNM Physics Department
E-Mail: diamond (at) unm (dot) edu
WWW: http://www.swcp.com/~diamond
States don't have rights. People have rights.
LHW
>I'm tired of the "Falling Bullet's lethal?" thread. All I want to know is,
>how many pounds per square inch can the human skull take before it is
>pierced? If someone out there says the terminal velocity of a bullet is
>150f p/s then what force would this exert on a human skull, and likewise
>what is the threshold of force upon the human skull before it can be
>penetrated by a falling object.
>
Force = Mass x Acceleration?
I think that if the Mass is increased, it affects the Force mor than
an increase in the accleration.
Me thinks.
- LHW
LHW
>I'm tired of the "Falling Bullet's lethal?" thread. All I want to know is,
>how many pounds per square inch can the human skull take before it is
>pierced? If someone out there says the terminal velocity of a bullet is
>150f p/s then what force would this exert on a human skull, and likewise
>what is the threshold of force upon the human skull before it can be
>penetrated by a falling object.
>
I hate to post again - but I just think i remembered something.
I remember reading a story about how WWI airplanes used to drop metal
darts into the trenches of enemy troops - these darts were effefctive
enough to penetrate the helmets and skulls of the troops below.
- LHW
jo...@diespam.net
a LARGER amount than acceleration, then yes it will affect the force
more, but if the mass is increased at the same rate as the
acceleration, they will have an equal effect on the force, and if mass
increases less than an increase in acceleration, then the acceleration
has a larger effect on the force.
lw...@abs.net (LHW) wrote:
>On 24 Jul 98 17:28:22 GMT, "Chris Bereznay" <br...@bigfoot.com> wrote:
>
>>I'm tired of the "Falling Bullet's lethal?" thread. All I want to know is,
>>how many pounds per square inch can the human skull take before it is
>>pierced? If someone out there says the terminal velocity of a bullet is
>>150f p/s then what force would this exert on a human skull, and likewise
>>what is the threshold of force upon the human skull before it can be
>>penetrated by a falling object.
>>
>
>
David CL Francis
>Considering that I easily fall at ~150mph when I skydive, which is
>220fps, and a bullet w/ a much more aerodynamic shape and less surface
>And the amount of pressure exerted is determined by the amount of area
>it is going over will also vary - I.E. if it is exerted on a point,
>the pressure approaches infinity.
>
>So...my point is that a majority of the time, a falling bullet hitting
>someone in the head WILL kill them.
I can't resist these threads I must stop!
The smaller an object the greater the drag compared to its mass. A 0.01"
diameter ball of tungsten will fall very slowly and could never hurt you
its energy would also be very low. As the size increases the terminal
velocity increases as does the objects mass and the energy increases
rapidly. the streamlining effect of the bullet affects the result but
not the basics. Incidentally if you dropped a bullet out of your
aircraft it would almost certainly tumble increasing its drag.
I assure you that a tiny mouse dropped from an aircraft has a much
better chance of survival than you do if you forget your parachute!
A small ant dropped from an aircraft will survive unhurt. This is why
mice can fall further than elephants without hurting themselves!
--
--------------------------------------------------------------
David CL Francis E-Mail reply to <da...@dclf.demon.co.uk>
--------------------------------------------------------------
Houghton
>The smaller an object the greater the drag compared to its mass. A 0.01"
Not necessarily. A ping pong ball and a sinker can be the same size,
and will therefore have the same drag. They will have different mass
though.
>diameter ball of tungsten will fall very slowly and could never hurt you
>its energy would also be very low.
Maybe...
> As the size increases the terminal velocity increases as does the objects mass and the energy increases
>rapidly.
No. The terminal velocity is the balance between drag and gravity.
Drag varies only with mass and surface area. Gravity is a constant,
while the force of gravity is related to the mass of the object.
the streamlining effect of the bullet affects the result but
> Incidentally if you dropped a bullet out of your
>aircraft it would almost certainly tumble increasing its drag.
Agreed.
>I assure you that a tiny mouse dropped from an aircraft has a much
>better chance of survival than you do if you forget your parachute!
Also agreed. A mouse is relatively lightweight, and so has a fairly
light bone structure. But you would also have to consider that a
mouse is much more delicate than a human. A mouse may have a lesser
density than humans, but it would take less of an impact velocity to
kill it.
>A small ant dropped from an aircraft will survive unhurt. This is why
>mice can fall further than elephants without hurting themselves!
Ants have a lower density than elephants. Ants are very simple
organisms. Cardiovascular system isn't complicated, made from a hard
candy shell (no skeletal structure). An elephant is huge, and has
evolved into a very complex organism that must be built very strong to
hold up to its own weight. An ant will survive a large drop because
its surface area : mass ratio is quite large.
>--
>--------------------------------------------------------------
>David CL Francis E-Mail reply to <da...@dclf.demon.co.uk>
>--------------------------------------------------------------
Perhaps these should be posted to sci.physics, but I imagine most
there would laugh at this conversation. Many posts in there deal with
QM, strange paradoxes, and faster than light travel.
Mike Houghton
UIN #8932708, contact me for Longbow 2.
David Geesaman
>
> On 24 Jul 98 17:28:22 GMT, "Chris Bereznay" <br...@bigfoot.com> wrote:
>
> >I'm tired of the "Falling Bullet's lethal?" thread. All I want to know is,
> >how many pounds per square inch can the human skull take before it is
> >pierced? If someone out there says the terminal velocity of a bullet is
> >150f p/s then what force would this exert on a human skull, and likewise
> >what is the threshold of force upon the human skull before it can be
> >penetrated by a falling object.
> >
>
> I remember reading a story about how WWI airplanes used to drop metal
> darts into the trenches of enemy troops - these darts were effefctive
> enough to penetrate the helmets and skulls of the troops below.
>
> - LHW
Skydivers and darts are capable of falling in the same orientation, but
a bullet seems more susceptible to tumbling motion. I can see a dart
killing because you can sharpen the tip and add mass to the dart, and
ensure steady flight. It will fall faster, carry more energy, and
concentrate that energy at impact. I guess we really need practical
input about the falling motion of a bullet or an experiment.
--
David L. Geesaman
David CL Francis
<houg...@georgian.net> writes
>Ants have a lower density than elephants. Ants are very simple
>organisms. Cardiovascular system isn't complicated, made from a hard
>candy shell (no skeletal structure). An elephant is huge, and has
>evolved into a very complex organism that must be built very strong to
>hold up to its own weight. An ant will survive a large drop because
>its surface area : mass ratio is quite large.
We are getting closer but there is simple relationship which for the
sake of argument has been called the "square/cubed" law. If you double
the size of an object its mass increases by the cube of the the linear
dimension. Its strength increases generally only by the square of the
dimension. So for the same material large animals have to have
proportionally thicker legs and bigger muscles than tiny ones. Its drag
also increases as the square of the linear dimension.
You are right about the ant surviving because its surface area/mass
ratio is large. My point is that this can be generalised and is a
fundamental physical trend. Large heavy aircraft are possible because of
improvements in structural techniques and because materials have
gradually improved as well.
Elsewhere I showed that the terminal velocity of a sphere made of say
iron depends on the square root of its diameter. However the energy at
terminal velocity depends on the fourth power of its diameter. Thus the
larger an object the greater energy it has at terminal velocity per unit
mass.
Double the size of a man and his terminal velocity would be 1.414 times
as great but his kinetic energy would be 16 times as great. (His mass
would be 8 times greater). But since, generalising, his strength would
be only 4 times greater his impact with the ground would be much more
severe.
I realise that in practice people vary in shape and that ants don't
scale exactly the same way as men!