Could someone build me a physical version of this?
Thinking of conservation of momentum, it seems like an engineer's nightmare (or a physics teacher's dream).
Anybody else agree? My physics is admittedly a bit rusty.
If allowed to be a decent size (not wrist watch size) would not be so terribly difficult to build.
A belt (or chain) from main hour hub to minute hub drives a gear stack. Gear stack drives the minute hand and the belt to the second hub, where another simple gear drives the second hand.
You may have to be satisfied with one of these: