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Nessuno si aspetta l'Inquisizione spagnola.

La fisica dei campi da tennis 04.07.15

Esistono oltre 160 superfici diverse su cui giocare a tennis.
Grantland ha raccolto le analisi su come queste superfici possono influire sul gioco.

The most important factor is the "coefficient of friction," a measurement of the abrasive force between the ground and the tennis ball. Courts with high frictional coefficients interfere with the movement of the ball, disrupting its forward momentum. Think of a sluggish clay court. According to experiments performed by the ITF, a shot hit without spin and traveling at 67 mph will lose about 43 percent of its ground speed after contact with the clay surface, slowing down to a leisurely 38 mph. (The reason clay steals momentum is rooted in the friction of all that loose brick, which clumps around the ball. Each clump is like a little speed bump.) As a result, players have a few extra milliseconds to hit a return.