THE DYNAMICS OF A GOLF BALL 



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So far I have been considering imderspin. Let us now illustrate 

 slicing and pulling; in these cases the ball is spinning about a vertical 

 axis. I must therefore move my electromagnet, and place it so that 

 it produces a vertical magnetic force (Fig. 23). I make the force act 



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^— -"•*""■—«-.,... 



Fig. 23. 



one way, say downwards, and you see the particles curve away to the 

 right, behaving like a sliced ball. I reverse the direction of the force 

 and make it act upwards, and the particles curve away to the left, just 

 like a pulled ball. 



By increasing the magnetic force we can get slices and pulls much 

 more exuberant than even the worst we perpetrate on the links. 



Though the kinks shown in Fig. 20 have never, as far as I am 

 aware, been observed on a golf links, it is quite easy to produce them 

 if we use very light balls. I have here a ball A made of very thin 

 india-rubber of the kind used for toy balloons, filled with air, and 

 weighing very little more than the air it displaces; on striking this 



Fig. 24. 



Fig. 25. 



with the hand, so as to put underspin upon it, you see that it describes 

 a loop, as in Fig. 24. 



Striking the ball so as to make it spin about a vertical axis, you 

 see that it moves off with a most exaggerated slice when its nose is 

 moving to the right looking at it from the tee, and with an equally 

 pronounced pull when its nose is moving to the left. 



