Editor’s note: With the U.S. Open serving up in New York this week, GW Today asked Alexander van der Horst, Physics Department chair at the Columbian College of Arts and Sciences and a veteran tennis tournament player himself, to break down in his own words the effects of different surfaces—from the grass of Wimbledon to the clay of the French Open to the Arthur Ashe Stadium hardcourt.
Among the physics principles that apply to each surface, the biggest one is friction. It impacts the pace of the game, the spin of the ball and the height of the bounce.
Clay has the most friction, grass the least and hardcourts are sort of in-between.
Clay’s friction slows the ball when it hits the surface. It also gives the ball more spin; the surface tries to slow the bottom spin of the rotating ball, but the top gets an extra spin—or top spin. At the same time, the friction causes more vertical movement than horizontal. The ball actually bounces higher.
So on the friction-heavy clay, you get slower ball speed, more spin and higher bounces.
Grass is the other extreme. It has very low friction, so the pace is faster. There’s less spin; the ball almost rotates backward for a backspin or a slice. And there’s a lower bounce.
The hardcourt at the U.S. Open this week is kind of in the middle—a medium friction for a medium pace, spin and bounce.
Clay and grass courts call for very different types of play—that’s why you have clay specialists (like Rafael Nadal) and grass specialists (like Roger Federer). But different styles basically even out on the hardcourt. Players with varying styles often do pretty well at the U.S. Open.
At this U.S. Open, I’m hoping for another great battle in the men’s final between Jannik Sinner and Carlos Alcaraz, just like Wimbledon and the French Open earlier this year. On the women’s side, Aryna Sabalenka and a few American women have the best chances, but I’m hoping that Iga Świątek will come out victorious.
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