[ExI] spinning space wrenches was: RE: Space governance

[spike at rainier66.com]

From: spike at rainier66.com <spike at rainier66.com> 
.

 
>.Usually the physics jockey hafta explain everything to us bonehead
engineers, but we show them this, which appears to defy conservation of
energy.  It doesn't, and it isn't magic.  We controls engineers have
equations which deal with products of inertia and even have that icky
coefficient of friction that physicists don't like to deal with, all those
distasteful non-linearities, swoon.. That isn't what happens.  More later if
I get time.  spike
 
 
There is an experiment I have wanted to do for a long time but I live where
the temperature hasn't been cool enough for the past 24 years.
 
Get a container with enough water to create a perfectly smooth sheet of ice.
Might need to leave it out, freezes, go over it with a cool iron (the kind
we used to press a crease in trousers a looooong long time ago) creating a
thin layer of water like a miniature Zamboni, let it re-freeze so you get a
sheet of perfectly smooth ice.  Then spin a tippee top on that.  Demonstrate
that without friction, it cannot get to its feet.  Reasoning: to raise the
CG, the spinning top has to borrow rotational energy and dump some of it in
the process.  Ah, got you there, say the physicists.  Are you claiming
rotational energy is lost to potential energy?  No, reply the bonehead
engineers.  We know that angular momentum is conserved.  A bit of the
angular momentum from the tippee top goes into rotational energy of the
planet.  Without friction, the tippee top can't dump that angular momentum
and cannot get to its. foot.
 
Fun aside: those same equations explain why you have never seen a scaled-up
tippee top.  
 
Ja I know it is mind-boggling, but all the conservation laws still work:
nothing failed.
 
spike
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