Physics: The effects of an underinflated football | Bob's Blitz

Physics: The effects of an underinflated football

physics under-inflated football
You know the New England Patriots did not under-inflate 11 of 12 footballs purposely if they thought a 7% reduction in pressure was not going to have a marked effect on Tom Brady's ability to throw them and his core's ability to catch them. Dr. John Eric Goff, a physicist at Lynchburg College in Virginia and author of Gold Medal Physics, writes:

Bad weather, like the rain and wind in the Pats win over the Colts, will make a quarterback desire a better grip on the ball. Water on the ball, after all, reduces friction between the ball's surface and the quarterback's hand. Anyone who has ever tried to palm a basketball, but finds one's hand just a wee bit too small, has noticed that palming the ball becomes easier if the basketball is slightly deflated. Deflating a football slightly allows for better grip, too.

Oh, and the good doctor, in an appearance on NPR, even had the deflated by 2psi number exactly pegged before sources revealed the number. Goff told Geoff Brumfiel of NPR's All Things Considered: "If you reduce the mass of the ball, which happens if you let a little bit of air out, the ball can decelerate faster when you throw it," he says. And that means it won't go as far on each throw."

physics under inflated football
"Deflating the ball does give a team an advantage," stated materials scientist Ainissa Ramirez, the author of Newton's Football, a book about the science of football. Ramirez says the slightly softer football improves the grip.

"Particularly during that game which was very rainy, it's hard to hold the ball, it's hard to catch the ball," she says. "So by making it a little softer, it's easier to catch the ball."

Ramirez also said tampering has happened before. In the 1990s, kickers in the NFL were secretly trying to soften up the ball to make it go farther. They tried all sorts of tricks: "Microwave it, hammer it, Gatorade it, steam bath it, put it in the dryer. Inflate it. Deflate it," she said.

Folks have asked, "Why didn't refs notice the deflated balls?" Dr. Goff reports: "Referees are supposed to inspect balls used in games. A referee sets the ball on the field before the start of each play. As I told Geoff Brumfiel, an under-inflated ball may not have been noticed by a referee hurrying to place a ball on a play or two, but should have been noticed if balls used for most plays were under-inflated. Nobody wants to think conspiracy when trying to figure out what happened, just like nobody wants to think a referee is incompetent or that a team cheated."

Both scientists agree the major effect that would be seen here is the grippiness, for throwing and for catching, is improved by an under inflated football. As Tom Brady stated in 2011, "I like the underinflated football." Proven to have been orchestrated by Bill Belichick? Minimum one year suspension. (Life would be appropriate.)

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