Warp wrote:
> Paul Fuller <pgf### [at] optusnetcomau> wrote:
>> Sorry but you are just wrong.
> 
>   It's easy to say "you are just wrong" without actually explaining why.
I actually do explain more after that one line that you quoted.
> 
>> In this case you assert that there is a point at which the cables can be 
>> attached that will prevent the stopping action from imparting any spin 
>> to the parent body.
> 
>   Attach the cable to the opposite side of the parent body. What happens?
When the cable goes taut the projectile will exert a force on the body 
(and vice versa) that will be off centre and will cancel the rotation. 
Of course things will bump around but once that is finished the net 
rotation will be as before the projectile was fired.  At every stage if 
you care to add up the angular momentum of the system it will be constant.

I can't reply with numbers and formulae unless you can give a diagram 
with distances, masses and velocities.
> 
>   Besides, we can just forget the cable: Simply shoot the projectile and
> that's it. With the correct amount of speed it will stop the object from
> rotating. Where did the angular momentum go?
It is carried in the off centre velocity of the mass of the projectile.
> 
>> No system of cables, pulleys, magnets, gyroscopes, friction, 
>> electricity, radiation, carbon nonotubes, superconductors or whatever 
>> can alter that.
> 
>   Since a spinning object can be used to produce energy (eg. by friction)
> you are effectively saying that a spinning object is an infinite source
> of energy because its angular momentum will never disappear.
> 
Absolutely not and it is revealing that you misunderstand or 
misrepresent the argument to that degree.  I'm not talking about the 
rotation of any single part of the system being constant.  I'm talking 
about the sum of the angular momentum of the whole system.

As the rotation of a mass A is reduced, an opposite change in angular 
momentum occurs somewhere else in the system.  And not by magic.  simply 
ask what is exerting the tangential force to slow down A and you'll find 
an equal and opposite force acting on that other thing.  And please 
don't say friction is exerting the force!  Some other part of the system 
must be applying the force be it via friction or any other means.

That you make just nonsense statements on my behalf then tear them down 
is poor style.

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