Re: Henry LaMothe
Title: Re: Henry LaMothe
About a year ago I found an interesting
problem in a Physics book about Henry
LaMothe (hope I spelled that correctly). It seems Henry had an
act in which
he would dive off a 40 foot tower and belly-flop into 1 foot of
water. It
seems impossible but they had a picture of this act in the
book. Now I can't
remember in which book it was and I have not been able to find it in
the books
around my office. Does anyone know in which Physics textbook I
saw this?
Thanks
Russ
This is in the 6th edition of
Halliday, Resnick, Walker Fundamentals. They give height as 30 m,
water depth as 30 cm and say that M. LaMothe did his act until he was
in his 90's.
A related set of interesting
problems involve surviving impact on the ground after jumping out of
an airplane without a parachute. I got this information from George Benedik and Felix Villars, in Physics With
Illustrative Examples From Medicine And Biology, Volume 1,
Addison Wesley, 1973, report that the threshold for human survival is
when the pressure on impact is less than 50 pounds/square inch. If
the fall is onto a person's back of area 3.8 square feet, the
threshold force for death is 27,000 pounds = 1.2 x 10^5
N.
In a fall from high altitude, the change in momentum
is fixed by the terminal velocity before impact, and the velocity of
0 after what we hope is not "Terminal" impact. Consider the
following observations. Do they satisfy this criterion for
survival?
"During one of
the battalion drops, from 1200 feet on a clear, relatively warm day,
an observer noted what appeared to be an unsupported bundle falling
from one of the C-119 airplanes; no chute deployed from the object.
The impact looked like a mortar round exploding in the snow. When the
aidmen reached the spot they found a young paratrooper flat on
his back at the bottom of a 3 1/2 foot crater in the snow, which
consisted of alternating layers of soft snow and frozen crust. He
could talk and did not appear injured; nevertheless, he was air
evacuated to a hospital. His only injuries were an incomplete
fracture of a clavicle, a chip fracture of L-2, and a few bruises. He
was released from the hospital in time to return south with his
unit."
Alaska, 1955
"[O]n the frigid 23rd of March, 1944, Flight Sergeant
Nicholas Alkemade, an RAF rear gunner [had his bomber set afire] by a
German night fighter on a raid over Hamburg. [H]e found that he was
unable to reach his parachute, stowed forward in the flaming
fuselage. Deciding he didn't care to burn alive, he jumped without a
parachute just as the aircraft exploded above him. His altitude was
18, 000 feet. Falling at a terminal velocity of about 120 mph during
this 3 1/2 mile fall (which lasted about 90 seconds), he struck the
snowy branches of a pine forest and then landed in less than 18
inches of snow, only twenty yards from the bare open ground.
Incredibly, his only reported injuries consisted of superficial
scratches and bruises, and burns received prior to the jump."
From "Terminal Velocity Impacts Into Snow", R. G. Snyder.
Military Medicine 131, 1290-1298 (1966).
--
Dr. Vern Lindberg
716-475-2546
Department of Physics
Fax
475-5766
85 Lomb Memorial Drive
Rochester Institute of Technology
Computer Haiku
Rochester, NY 14623
A
file that big?
It might be very useful.
But
now it is gone.