this is probably only a paradox to fools like me but here goes: a fly weighing microgrammes flies straight along a railway track.Coming in exactly the opposite direction is a freight train weighing x tons times its speed of say 2150mph. the fly hits the train and , naturally stops.At the fraction of a second that it is stopped it is obviously stuck to the train , ergo the train is stopped- surely that can't be right? - i've been waiting ages to ask clever people about this. it strikes me that it does not matter if it is a squishy fly or an atom- either way it is stationary when it touches the train and so must the train be stationary or motion is an illusion)I bet relativity comes into this somewhere)
What makes you think that the train stops? The change in momentum that the train experiences is negative when the fly hits it, but the train's momentum doesn't change signs nor is zero at any point.
The change in momentum that the train experiences is negative when the fly hits it, but the train's momentum doesn't change signs nor is zero at any point.
neither does train run straight, there are miniscule variations in everything in this universe, nothing is truly perfect to be considered "straight".
I infer, possibly wrongly , that if the fly stops and is stopped and stuck to the train both are stopped much as if the front of the train stopped so would the back
if the fly stops when it touches the train, it is stuck to the train as much as the back of the train if the train is stuck to, or touching something stationary, ergo the train is stationary also
a molecule of the train is still the train, if a molecule of the train stops so does the train just as the back of the train stops when the front stops
Actually the back of the Train doesn't stop when the Front of the Train stops, that action is called Run On.
