On 08/11/14 22:28, Ed Huntress wrote:
On Sat, 8 Nov 2014 17:25:43 -0500, "Jim Wilkins"
wrote:

"Gunner Asch" wrote in message
news
On Sat, 8 Nov 2014 14:06:22 -0500, "Jim Wilkins"
wrote:

"Gunner Asch" wrote in message
...
On Wed, 5 Nov 2014 00:48:07 +0100 (CET), "corman"
wrote:

The 1-pound tape measure became dislodged from the belt of a
worker on the 50th floor and struck construction equipment about
10 to 15 feet from the ground, spokeswoman Carly Baldwin said.

It then ricocheted and struck 58-year-old Gary Anderson, who had
just stopped to speak with another worker who was in a pickup
truck.
If it ricocheted..the hardhat may not have done him a lick of
good.
Coming in from the side..hard hat isnt going to help unless your
head
is canted just right.

That being said...anyone care to calculate the footpounds of
energy
that a 1 POUND item will develop after a 50 story fall? (figure
12'
per story and a rate of fall of 32fps/fps and then deduct
humm...25%
for the impact of the ricochet.

Height = 600 feet/ 182.8 meters
Weight of falling rule = 1lb or .4535kg

speed at impact 196 fps/59 m/s

Fall time 6 seconds

Do the math

He would have been unlikely to survive even wearing the hard hat.
It
would have driven his skull sideways on his neck and snapped it
like
a
twig remember..it was no longer a straight drop..but one at an
angle
after the ricochet.

Given the quality of the hard hat..it may simply have blown a hole
in
it..or driven the hat into his brain as it deformed. Blunt
trauma
in
this sort of impact load is fatal in any CNS strike.

Anyone care to give us the impact force in psi and n?

Gunner
The potential energy at the top is Mass * g * height. At the bottom
it
has been converted into the same amount of kinetic energy.
https://www.chipola.edu/instruct/sci...workenergy.htm

Since I don't know the exact numbers these are rounded.
0.5KG * 10m/S^2 * 180m = 900 Joules (kg * m^2/s^2)

That equals 1 HP for 1.2 seconds, which could drill a fair sized
hole.
http://wredlich.com/ny/2013/01/proje...topping-power/


I cam up with something like 575 Footpound at an impact speed of
196
FPS in a surface area that is all corners. Might not have Exploded
his head..but it damned sure would have embedded that measure in his
skull if not passing completely through.
Compare that 900 J to crash helmet ratings:
http://www.smf.org/docs/articles/dot
-jsw
I assume you guys are calculating air resistance? d8-)

I doubt if it achieved anything close to its theoretical speed in a
vaccum.

On a BBC program recently they filmed the dropping of a bowling ball and
feathers in the worlds largest vacuum chamber both with and without air,
pretty impressive. The drop in vacuum here
http://www.wired.com/2014/11/droppin...acuum-chamber/