text: what are the rules when balls collide??? if a player in a tounament lands his ball on the green in, say, one shot, close to the pin, and the next players ball lands on the green and knocks the first ball in the cup, what are the rules going to be about that?  is it a "hole in 1" for the first palyer? who is penalised if anyone? according to the usga rule 18-5 in the rules of golf : if a 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/playing/rules/rules_of_golf.html  it does not show a penalty