The Physics of a Tennis Ball’s Spin

Misleading title - the article asserts that spin wins matches without describing the physics at all. It's a barely-veiled advertisement for Wilson's rackets.

In tennis, the spin that "wins matches" is the topspin. In a topspin, the Magnus effect generates downwards lift, allowing the ball to be hit forwards faster and still land in the court than if downwards acceleration was provided by gravity alone. Without spin, unlimited-speed shots can only be hit at heights where the ball has near line-of-sight with the opposite court. Since hitting the ball faster than your opponent can get to it is what wins points, that's why spin wins matches.

But tennis is hardly the poster-boy for the Magnus effect. Table tennis has a small and raised court, and a high speed/mass ratio, which makes it apply the Magnus effect more completely than any other sport. Spin is used to to generate lift for long slow defensive shots, to attack from far below table level, and to alter ball direction in flight. Table tennis players require a good "feel" for all aspects of the Magnus effect in order to improve much more beyond beginner level, and no mid-level amateur player can ever get away with not thinking about it.

There's an excellent video submitted here:

https://news.ycombinator.com/item?id=9915197

about the Magnus effect. Quite simple and amazing.

The author says that Wilson's new racquet with Spin Effect technology doubled the spin on his shots compared to his normal racquet. Now that sounds mind-bending!

Especially when Wilson's site claims that technology provides the benefit of 10% more spin - http://www.wilson.com/en-us/tennis/spin-effect/innovation/