Original Issue

# Forces to Be Reckoned With

For readers willing to exert some mental energy, there's loads to learn about the science of the gridiron

FOOTBALL PHYSICS

by Timothy Gay

Rodale, 290 pages, \$21.95

According to University of Nebraska physics professor Timothy Gay, every time a quarterback scrambles out of the pocket and cocks his arm for an on-the-run toss, he has to solve a knotty physics problem in a split second. He must calculate the pass's velocity and downfield trajectory while factoring in his own cross-field velocity and his receiver's velocity in perhaps another direction. How in the world does a quarterback accomplish such a thing? Simple, writes Gay: He uses vectors--subconsciously, of course--just as Michael Faraday used vectors to formulate the laws of electricity and magnetism.

Befuddled? Intimidated? Well, you should be, because physics is wicked hard--much harder than, say, football. A football field is a puny 100 yards long and 531/3 yards wide, while the field of physics is infinite in all directions, and there are no cheerleaders to root you on from the sideline. By his own account, Gay was never much of a player (in the early 1970s, he writes, he stank up the defensive line for the Caltech Fighting Beavers), but he is a truly fine coach. To understand vectors, for instance, just think of the arrows John Madden scribbles with his Telestrator. "Vectors are arrows, nothing more," Gay writes. And thus, with Madden-like energy and enthusiasm, the professor makes it ... well, certainly not easy, but definitely possible, for ordinary fans to get a sense of the mathematical beauty that underlies this ferocious game.

Perhaps you already know that Dick Butkus used to crush his prey with more than 1,100 pounds of force (the weight of a smallish killer whale). Or that on a goal line surge an NFL offensive line expends as much kinetic energy as six shots from .357 Magnum handgun. Or that on a kickoff, the placekicker's foot touches the ball for roughly eight milliseconds. Or that it is the slower, heavier players, not the quicker ones, whose speed increases more on artificial turf (compared with grass). Or that the Wave almost always travels clockwise in a crowd, probably because most people are righthanded, and, like sound, moves more slowly in colder temperatures.

But even if you do know all of these facts, you probably don't know the reasons behind them, and you won't fully understand the game until you do. Some of this material can be tough going, but Gay helps by illustrating his points with examples fans will understand. For instance, how much of an advantage is it for the offensive line to know the snap count while the defense doesn't? "Remember the Ice Bowl," he writes. "The ball was one foot from the goal line. Two tenths of a second after the ball was snapped, the Dallas defense was faced with an oncoming Packers offensive line sporting about 10,000 lbm*ft/sec [pound (mass) feet per second] momentum and wanting nothing more than to move the ball 13 inches forward. Given that the Cowboys weren't even moving yet, this kind of momentum is hard to stop."

True, most fans will find this book more grueling than Bear Bryant's two-a-days in the Alabama heat. But those who get through even a chapter or two might never look at football the same way again. "The more you understand about football," says Gay, "the more you get out of watching it." So give yourself a shot--if you think you're tough enough.

TWO COLOR PHOTOS

RODALE INC (2)

COLOR PHOTO

RICK HAVNER/AP

POWER BALL

A tackler, Gay observes, can hit with more than 1,100 pounds of force.