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Consider the following mechanical system
A thin tube can rotate freely in the vertical plane about a fixed horizontal axis passing through its centre ##O##. A moment of inertia of the tube about this axis is equal to ##J##. The mass of the tube is distributed symmetrically such that tube's centre of mass is placed at the point ##O##.
Inside the tube there is a small ball which can slide without friction. The mass of the ball is ##m##. The ball can pass by the point ##O## and fall out from the ends of the tube.
The system undergoes the standard gravity field ##\boldsymbol g##
It seems to be evident that for typical motion the ball reaches an end of the tube and falls down out the tube. It is surprisingly, at least for the first glance, that this system has very many periodic solutions such that the tube turns around several times during the period.
For details seehttp://www.ma.utexas.edu/mp_arc/c/16/16-60.pdf
http://www.ma.utexas.edu/mp_arc/c/16/16-61.pdf
comments are welcome
A thin tube can rotate freely in the vertical plane about a fixed horizontal axis passing through its centre ##O##. A moment of inertia of the tube about this axis is equal to ##J##. The mass of the tube is distributed symmetrically such that tube's centre of mass is placed at the point ##O##.
Inside the tube there is a small ball which can slide without friction. The mass of the ball is ##m##. The ball can pass by the point ##O## and fall out from the ends of the tube.
The system undergoes the standard gravity field ##\boldsymbol g##
It seems to be evident that for typical motion the ball reaches an end of the tube and falls down out the tube. It is surprisingly, at least for the first glance, that this system has very many periodic solutions such that the tube turns around several times during the period.
For details see
http://www.ma.utexas.edu/mp_arc/c/16/16-61.pdf
comments are welcome
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