Hard for me to admit my faults of education, but am pretty weak on classical physical notions.
Yesterday at the European PGA event, Padraig Harrington's ball on the first bounce went into the cup then bounced out of the cup to lie nearby on the green.
The rules state that the ball in the cup must be at rest on the bottom of the cup to be holed. Now, if we had installed a tiny camera near the bottom of the cup, and cranked it up to record 100K frames per second, would we see the ball hitting the bottom of the cup, then stopping for an instant, and then deforming slightly and finally rebounding out? Or would we see in those nanoseconds the ball never at rest, always moving either down or up?
Of course all this relates to the absurd, IMO, use of the cameras peering at the ball greenside and the rules judges making asses of themselves, the next day from the armchairs, over minute and arguable decisions on ball movement/oscillations that happened at the big tourney, yesterday.