sicetaitsimple wrote:-And yet they twirl, rising, falling depending on the moment.
if it was simple told me on another forum that a dead leaf that sometimes falls rises.
I said to myself that assuming at first that it is dimensionally stable, it was impossible for its center of gravity to rise whatever the moment of its fall.
In other words, I told myself that z(t), the height z of this center of gravity measured as a function of time, was necessarily a monotonically decreasing function. I think it is the same if it is deformable.
But I'm not sure.