Physics of Basketball

Well, at least, the physics of the new NBA basketball, at any rate…

For those who haven’t heard the story already, the NBA is changing the style of the basketballs used in its games this season. They’re moving away from the traditional leather basketballs to a new synthetic material, which is supposed to hold up better to wear and tear.

Predictably enough, most of the players hate the new ball, and Mavericks owner Mark Cuban has gone so far as to enlist physicists to look into the situation:

Jim Horwitz is chair of the physics department at UT-Arlington, and Kaushik De is the project leader and a physics professor at UTA. They were asked by Mavericks owner Mark Cuban to do a study about the differences between composite and leather balls.

What the physicists found was that the new ball, when dropped from a height of five feet, bounced an average of four inches lower than the old ball. In addition, the synthetic ball was much slower to absorb moisture, a key complaint among players who seem to be constantly losing their grip on the new spheroid in the preseason.

Ahh, the glamorous life of a scientist… Were the guys from Mythbusters busy this week?

8 comments

  1. I love the rationale, worn out balls must cost the NBA something like 12$ a year, it is therefore crucial to cut down this expense 10% or so…I am wondering if there was a more convincing reason given for the change.

  2. Since a child would notice the less bounciness of the ball, the sub-text is that by invoking physicists, they want to give this the authority of science. It would be better for the players’ case if the physicists had said 4.2 inches, it sounds more authoritative. Plus most people could figure out how to estimate the 4 inches, but the precision implicit in 4.2 inches would have stymied them.

    A player could have held a ball in each hand of each kind and dropped them together on the playing floor. Point made.

    This, IMO, is a total misuse of the standing of science.

  3. Can they not play the game with multiple new balls and wipe the sweat off? 70g water absorption must make quite a difference with the leather ball.

    Speaking of basketball, does anyone know why the 3-point arc is where it is? For instance, Stojakovic has shot 40% from behind the arc throughout his career, but I know he doesn’t shoot 60% otherwise (don’t have the exact stats — nba.com seems borked).

  4. I heard that the new balls cost $100 each, so I don’t think cost-savings is really an issue. What we’ve got, here, is a way to charge an outrageous amount for branded merchandise…

  5. Can they not play the game with multiple new balls and wipe the sweat off?

    I’m sure you could, much like they do in baseball, but when would you make the switch? Basketball is a much faster game, with near instantaneous restarts in most situations. Inconsistent switching of game balls during a game will be perceived as favoritism toward one team or another.

  6. Professional sports players are almost guaranteed to hate any change to their standardized equipment. It screws up all those finely adapted “reflex arcs” (terminology?) they’ve spent thousands of hours training into their spinal cords.

  7. Soccer players freaked out similarly when a new type of ball was introduced during the recent World Cup, but they apparently got over it.

    Last night the Mythbusters fired a compressed air cylinder through a cinderblock wall by knocking the valve off. It was definitely in the “applied physics is fun” category.

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