After how many metres can the ball go in when taking a free hit ?
( Note : Knocking over pins with the red object ball on an otherwise legal shot is not a foul , and has no effect on the score ( i.e. , provided that the opponent 's cue ball was struck first by one 's own cue ball , either cue ball can be used to drive the object ball into the pins , provided that both cue balls make initial contact with each other . )