1st golfer gets his ball on the green. 2nd golfer also gets his ball on the green. But the 2nd golfers ball rolls into the 1st ball. The 1st ball drops into the hole Is that a hole in one for the 1st golfer? I assume it is.
I believe the first ball must be placed back at it's location prior to being hit. Now if the second ball hit the first and then went into the hole that would be a hole in one. It's been a while since I played so I'm not 100% sure about the rules for this situation.
No. If the first ball was hit by the second ball and went into the hole, the first ball would have to be replaced at its original spot. OTOH, imagine a "blind" tee shot, (i.e. one that could not be readily observed by either player) and this exact scenario unfolded. Odds are the first player would take the hole in one and be none the wiser. Golf = a sport with far too many rules in which even the rules "officials" can't agree on many of the arcane technicalities.
Strange as it was to see 3 aces on #16 on Sunday.... wasn't there was a PGA event years ago where 4 players made an ace on a particular hole within 45 minutes?
18-1. By Outside Agency If a ball at rest is moved by an outside agency, there is no penalty and the ball must be replaced. Note: It is a question of fact whether a ball has been moved by an outside agency. In order to apply this Rule, it must be known or virtually certain that an outside agency has moved the ball. In the absence of such knowledge or certainty, the player must play the ball as it lies or, if the ball is not found, proceed under Rule 27-1. (Player's ball at rest moved by another ball - see Rule 18-5) 18-5. By Another Ball ball in play and at rest is moved by another ball in motion after a stroke, the moved ball must be replaced. http://www.usga.org/rules/rules-and-decisions.html#!rule-18
IOW, as I suggested earlier...If the first players ball is hit by the other ball into the hole (and was not observable from the tee area), the first player would have a technical Hole-in-one, even though it was moved by an "outside agency". To further complicate matters, if someone on the next tee saw what took place, but didn't tell the players in the group and the player who hit the hole-in-one (as he believed it to be) signs the scorecard, he would be disqualified for signing an incorrect scorecard. The rules are an absolute mess.