From: edprochak@gmail.com   
      
   On Friday, March 23, 2018 at 7:51:24 PM UTC-4, John Heath wrote:   
   > On Wednesday, March 21, 2018 at 8:00:05 AM UTC-4, Edward Prochak wrote:   
   []   
   > >   
   > > The problem is that you are confusing angular speed and   
   > > angular momentum.  The angular speed is indeed different   
   > > after stretching the band, but the angular momentum of the   
   > > combined Person, elastic band, and turntable system remains   
   > > the same. This is because the moment of inertia changed also.   
   > >   
   > > Linear inertia is due only to the total mass of the object.   
   > > The moment of inertia is dependent on the total mass and the   
   > > distribution of that mass (IOW, its shape).   
   > >   
   > > So there is no rub which allows you to escape. It may be time   
   > > for you to do a little experimenting. Note that since you are   
   > > only dealing with the person, band and moving part of the   
   > > turntable, you can do the experiment at home.   
   > >   
   > > But again I suggest that the "band" be something massive that   
   > > can make a more significant change in the moment of inertia.   
   > >   
   > > It doesn't have to be elastic like a spring. A heavy weight   
   > > tied to two handles via pulleys. As you hold the handles   
   > > and widen your arms, it lifts the weight which is at the   
   > > center of the rotation. Make the handles something also heavy   
   > > (heavy enough to change the moment of inertia, but light   
   > > enough that even rotating, they can lift the heavy weight).   
   > >   
   > > But also, you really need to look at the equations and work   
   > > a few examples, to see that there is no free energy here.   
   > >   
   > > Enjoy,   
   > >   ed   
   >   
   > You have made some good point and I agree. From this let us establish   
   > a foundation that can be trusted.   
   >   
   > A]There is no free energy. All forms of energy must be accounted   
   > for.   
   >   
   > B] Linear momentum conservation in x y and z direction can not be   
   > violated.   
   >   
   > C] Angular momentum conservation may be violated by exchanging it   
   > for energy , stretch elastic band.   
   >   
   > You agree with A and B but you are not liking C.   
      
   It is not a question of like/dislike.  It is a case of having   
   done measurements and from those never observing violation of   
   angular momentum. This is why I suggested that you get out of   
   your thought experiments and into the lab to do some physical   
   experiments.   
      
   >                                                  If you have a   
   > stretched elastic band in your pocket caused by angular momentum   
   > and not willing to reduce angular momentum you in violation of A.   
   > Do you have an alternative source of energy that stretched the   
   > elastic band?   
   >   
   > [[Mod. note -- Your statement (C) is false.  Angular momentum   
   > is conserved, and there is no way to violate that conservation.   
   > As other people have pointed out, your stretched elastic band is   
   > not violating conservation of momentum.   
   >   
   > Your stretched elastic band is also not violating conservation of   
   > energy.   
   >   
   > It might be instructive to consider a different example of stretching   
   > an elastic band.  Let's consider a room on the Earth's surface,   
   > containing a heavy weight which is clamped in place, and an   
   > unstretched elastic band connecting the weight to the ceiling of the   
   > room.  Now move the tabletop out from under the weight, so that the   
   > weight falls down to the floor, stretching the elastic band as it   
   > does so.  For simplicity, let's assume that the elastic band stretches   
   > sufficiently to slow the weight's fall such that the weight comes to   
   > a stop (zero instantaneous vertical velocity) before the weight hits   
   > the floor, and that at that moment we then clamp the weight again.   
   >   
   > So... we now have a stretched elastic band.  Where did the energy   
   > come from to do that stretching?  Clearly it came from the gravitational   
   > potential energy of the weight, i.e., it came from the Earth's   
   > gravitational field doing work on the weight as the weight fell down   
   > towards the Earth's center.   
   > -- jt]]   
      
   Much thanks to our esteemed moderator for the additional example.   
      
   John Heath,   
   you seem to be searching for a means to escape the conservation   
   of energy. Many others seem to follow this same path (as judged   
   by the many flawed perpetual motion videos on youtube). The motion   
   of rotation is one that fascinates us humans (evidenced by how many   
   amusement rides are based on rotation!).  Verbal descriptions   
   fail in conveying the interactions involved.  I sincerely suggest   
   more study and experimentation on your part, then your understanding   
   will come.   
      
    Ed   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)