RE: Hole in one ......12 Mar 2021 11:10
Trek,
I think the reason the fly and train confuses is that parts of the fly stop moving before other parts, hence the front end of the fly passing out is back end as it hits the train's windscreen. Alas for the fly, although easily deformed it is not elastic enough to fully resume it's original shape having changed direction!
Similarly the train itself also has to fractionally deform to absorb the impact of the fly, however the difference in inertia is such that the deformation of the train is so slight it isn't visibly noticed and so the train's windscreen is easily able to reform its shape from such a minor deformation.
If the fly were much more rigid such as a tiny ball bearing weighting the same as the fly, then it would have to be the window that did much more of the deforming and in that cases the glass might not so easily recover from that.