Is it theoretically possible for an object or particle to change to the opposite direction without making a complete stop first?
Lets say I have a fictional hammer swing setup like this:
I fire an electron to the hammer and the hammer smashes it back, is it possible for the electron (or any other particle or body) to change direction without slowing down and making a complete stop? If not, which law defines that?
Note: the question isn't about the hammer part but that was just the first thing that came up in my mind.