MythBusters - Hammer Jump
Peter Rees
THE MYTH
If you fall from a tall structure... say a bridge... into water, will
a hammer dropped slightly before you break the fall?
THE SETUP
The current security alerts in the united states prevented us from
getting onto any of teh Bay areas famous bridges. Instead we dropped
our 180lbs crash test dummy from a 180 foot crane.
The dummy was rigged with an accelerometer, and filmed with a high
speed camera operating at 1000 frames per second. The dummy was
attached to the cranes cable with two loose shackles at head and feet.
The crane ball was dropped to the bottom of the bay providing a guide
wire for the entire length of the dummies fall.
THE EXPERIMENT
The first fall took approximately 3 seconds. The impact was awesome...
so powerful lin fact that one of the dummies legs was torn off.
In all we ran six drops, three with a 60lb hammer attached to the
guide wire two yards in front of the dummy, and three without.
Despite the head and foot guides the dummy fell in all kinds of
orientations. The belly flop seemed to be the preferred method. In one
instance the dummy fell upright exactly in on the impact site of the
hammer.
THE RESULTS
The dummy reached a velocity of approximately 64 miles per hour. On
average the g force peaked around 270 g. In some orientations the
G-force reached 300 g. The dummy is built for impacts of 60 - 80 g at
consderably lower velocities.
ANALYSIS
Problem one... the human body naturally tumbles as it falls.
Problem two... a three second fall time leaves very little room to aim
your hammer and orientate yourself to fall perpendicular to the waters
surface.
Problem three... the hammer only punches a small "target" in the
water.
Problem four... even if you hit that target the advantage of dropping
the hammer is small enough to be incosequential.
CONCLUSION
Mythbusted...
Peter Rees
> UPDATE FROM THE MYTHBUSTERS SHOP
Man I can't believe this one has slipped through the cracks... I'm
reposting the hammer jump because I dan't believe that we really
covered all the bases to get this experiment through four days of AFU
without comment.
David Wnsemius
news:6b6b4da6.03062...@posting.google.com:
> pet...@beyond.com.au (Peter Rees) wrote in message
> news:<6b6b4da6.03062...@posting.google.com>...
>> UPDATE FROM THE MYTHBUSTERS SHOP
>
> Man I can't believe this one has slipped through the cracks... I'm
> reposting the hammer jump because I dan't believe that we really
> covered all the bases to get this experiment through four days of AFU
> without comment.
>
>>
>> THE MYTH
>> If you fall from a tall structure... say a bridge... into water, will
>> a hammer dropped slightly before you break the fall?
snip
I read it, thought: that will be good to see, ... couldn't find anything
wrong with it. The bit about the dummy failing to fall feet-down reminded
me of the trick with falling playing cards. If you want them to fall
straight down, you need to orient them parallel to the floor. If you drop
them while oriented perpendicular to the floor they will tumble and slew to
the side.
--
David "coulda' tried concrete sneakers I s'pose" Winsemius
It's the difference between stopping at a finite value of n and letting
n go to infinity.
-Harold Buck searches for closure on AFU
Lee Ayrton
> I read it, thought: that will be good to see, ... couldn't find anything
> wrong with it. The bit about the dummy failing to fall feet-down reminded
> me of the trick with falling playing cards. If you want them to fall
> straight down, you need to orient them parallel to the floor. If you drop
> them while oriented perpendicular to the floor they will tumble and slew to
> the side.
The same trick can be used to force the result of a coin toss. If you
propel it upwards with a flick of the arm rather than the thumb it will
appear to tumble in flight but will usually land in the same heads/tails
orientation that it started it.
Lee "Dunninger's" Ayrton
Dr H
On Wed, 25 Jun 2003, Lee Ayrton wrote:
}The same trick can be used to force the result of a coin toss. If you
}propel it upwards with a flick of the arm rather than the thumb it will
}appear to tumble in flight but will usually land in the same heads/tails
}orientation that it started it.
At least half the time...
Dr H
Kevin D. Quitt
while tossing it up. The tap will put the coin at an angle, and it will spin
around the vertical axis - with the same side always up. The trick is to
calibrate the tap so it's not obvious that the coin is spinning. Anything from
30 degrees (and up) from horizontal will work, although 45-60 looks better.
Make sure you tap it *after* you've started it spinning, so that it doesn't
flip.
--
_
Kevin D. Quitt 91387-4454 Ke...@Quitt.net
96.37% of all statistics are made up