Sunday, November 24, 2013

Ask Linda #750b-A “scientist’s” opinion on ball moving after address

Linda…I would like to play Devil's advocate on this one [Ask Linda #750-Gravity or address moves ball]. Physics tells us that a body at rest will only move if an outside force is exerted upon it (Newton's First law of Motion). A ball at rest can be sitting on a very steep slope but it will never move on its own because the frictional resistance at the point the ball is touching the putting surface is offsetting the gravitational forces of the slope. Now, if the slope is steep enough it might only take the wind generated by a gnat flying overhead, or a blade of grass under the ball growing one nanometer, but it will take some outside force that alters the balance between the frictional forces and the gravitational forces on the ball -- unless of course Newton was wrong.

So, while I agree with Decision 18-2b/11 in that gravity is not an element that can ever be considered responsible, I don't think this necessarily means a penalty stroke is required. I think this means the player needs to ascertain what that outside force was since gravity has been ruled out (both by physics and by rule). If that force came from grounding the club behind the ball and altering the terrain behind the ball in some small way it would clearly be a stroke. However, if it had to do with an insignificant breath of air acting on a ball that is sitting precariously on a "perch" or some other force outside of your control that got the ball started it seems that would be a different story. Just one reader’s opinion. 

Thanks, 
Lou from Texas

Dear Lou,

If your ball is perched precariously on a very steep slope, I would suggest that you approach it gingerly and refrain from grounding your club behind the ball. You will not incur a penalty for moving the ball if you have not grounded your club or engaged in any foolish activity that could cause it to move.

Once you address the ball, you cannot avoid the one-stroke penalty unless it is clear to everyone that something observable moved the ball (e.g., wind, water, or an outside agency). Note that the Rule [18-2b] states that if the ball moves after address “the player is deemed to have moved the ball.” The player may not have actually moved it, but he is deemed responsible under the Rules of Golf.

Again, the savvy golfer will not ground his club when he suspects his ball is unstable.

Linda
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