"Richard Smith" wrote in message ...

"Jim Wilkins" writes:

http://physics.wm.edu/~labs/110/110_pdf/ch4.pdf
If the metal permanently deforms some of the kinetic energy converts
to heat.

Resilient design - make sure that in an extreme event, there's
not-a-lot / no abrupt breaking (low energy and structure is lost) and
a lot of distributed bending and deformation (high energy, and the
structure is still there)... :-)

Job as a welder - repair a height-restriction barrier at a supermarket
http://www.weldsmith.co.uk/dropbox/m...tS_htbarr.html
"Insert plates" so knocking it over again would be a long energy
consuming process.
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Around here bollards that are expected to stop vehicles to protect buildings
are 4" nominal pipe set in and filled with concrete. 4" pipe is actually
4.50" OD, and I acquired some free 3.5" pipe which is 4.0" OD and was
mistakenly cut and painted yellow to be bollards.

The pipe came with an 8' x 10' wooden shed a neighbor bought at a yard sale
and brought home on his flatbed equipment trailer. He and his
construction-worker friends had used it as rollers to muscle the 2400 lb
shed onto the trailer. Then I was enlisted to hoist the shed off the trailer
and lower it onto its new foundation. The pipe may be useful as rollers this
spring when I move a 4000+ lb oak log off the hillside where it fell and to
somewhere flat enough to set up my sawmill.

When I was building custom industrial machinery we muscled as much as 5000
lbs onto the truck. That's about the average weight of a stone in the
Pyramids. Customer [XY] had his just-delivered machine up on a forklift when
the break time buzzer sounded and the crew just left it there. When they
returned the machine had fallen flat on its face and the forklift was
standing up on end. I salvaged a bucket of electro-mechanical components
like Variacs from the rebuild.

I was in line (queue) at the industrial supply store behind an
inventor/engineer who was picking up the 2" ID bearings he had special
ordered for the 2" water pipe support on his tracking solar array. He was
very unhappy to belatedly discover that 2" pipe isn't anywhere near 2.0" in
diameter. I warned him that although the specified OD is 2.375" it isn't
truly round unless cleaned up on a lathe, which removes the protective
galvanizing.

I machined the thrust bearing for my solar array from stainless plate and
turned the ball race grooves with the sharpened back end of a carbide drill
bit. The housing is a PVC pipe fitting.

This show why engineers and inventors need good techs. The designer of the
Japanese Zero naval fighter complained in his memoir that a wartime shortage
of competent technicians seriously hindered the development of its
replacement, and their Navy depended on its pre-war design long after US
fighters 100 Kts faster had made it a death trap. German designers made the
same complaint, and I believe their late-war proliferation of scatterbrained
schemes was self-preservation. Towards the end even U-Boot crews were being
drafted as infantry for the Eastern Front.
https://www.historynet.com/extremes-amerika-bombers.htm

https://en.wikipedia.org/wiki/Die_Glocke_(hoax)
Like every secret project it needed a misleading cover story. Segway leaked
some whoppers to conceal what we were doing in the lab.
To me the detailed description appears to be of a very powerful X-Ray
source, a Death Ray against bombers, which unfortunately could only shoot
straight up due to its parabolic rotating Mercury anode, Tungsten being too
desperately needed elsewhere.
https://en.wikipedia.org/wiki/Liquid-mirror_telescope
The proof-of-concept demo would of course use visible light, not X-rays.

The special Mercury may have been radioactive waste left from the recovery
of Radium metal by electrolysis, and perhaps the basis of "Red Mercury". The
round structure above would have held a lens or mirror to aim the beam of
X-rays, which is impossible with any known material, but ignorant
street-thug Nazi officials wouldn't know that. A convincing zapping demo
could be faked using a lens of silver chloride, which does focus equally
invisible infrared, and makes a plausible excuse to acquire large amounts of
the precious metal in a soft yellow/white form that could be smuggled into
Switzerland as cheese.