Football physics the science of the game timothy gay

Football Physics: The Science of the Game. Football Physics is the ultimate read for serious fans of America's most popular spectator sport. Relive pro football's legendary plays -- Franco Harris's Immaculate Reception, Joe Montana's scrambling pass for The Catch, Dick Butkus' ferocious drive-stopping defense -- while gaining a fresh appreciation for the dynamics of blocking and tackling, open-field running, kicking, passing, the struggle at the line of scrimmage and the role played by padding, turf and the decibels of sound generated by the home crowd.

Illustrated with classic NFL action photos and original diagrams that illuminate the natural laws governing this deceptively simple game, Football Physics is an outgrowth of Dr. Timothy Gay's playful, brilliant lectures that have been adapted for Blast!

Football Physics: The Science of the Game

After the football, the next most important piece of equipment on the field is the helmet. Unlike some of their predecessors, which were little more than leather skullcaps, today's technological marvels are remarkably successful in preventing serious head injuries. Basically, the modern helmet is a molded plastic shell that fits over the head, with a face mask and an interior lining of compressible material.

The advent of face masks, and the replacement of leather with plastic, were both developments of the early s. Duncan is in the end zone drawing a bead on what would be Warren Moon's third touchdown pass. Duncan himself, meanwhile, is being targeted by Kelso, who has built up a considerable head of steam.

The ball arrives, and a split second later Kelso bashes his helmet into Duncan's, causing Duncan's head to fly back like a limp doll's. Fortunately, Duncan is able to pick himself up following the hit and celebrate the touchdown, his head still attached. Unfortunately for the Oilers, they were about to blow the game in unforgettable fashion.

Trailing by 32 points in the third quarter, the never-say-die Bills, again led by backup quarterback Frank Reich, put on a dazzling display of offensive fireworks to not only get back in the game but ultimately pull out the victory in overtime,on a Steve Christie field goal.

It would go into the books as the greatest comeback in NFL history -- although the Oilers and their fans surely can be excused if they don't see it that way. Nothing could protect Duncan from the emotional whiplash he would soon suffer, but how did his helmet manage to protect him from physical injury?

We can answer this question by considering two physical quantities associated with a hit: pressure and impulse. We've talked briefly about impulse before, and we'll return to it in detail in a moment, but let's first consider pressure. Pressure is caused when a force is applied to a given football physics the science of the game timothy gay.

That's why we talk about pressure in units of pounds per square inch psi. Remember that in chapter 5 we blew up a football to a regulation pressure of 13 psi. Things can get tricky here, though, because usually when we talk about pressure in this context, we really mean pounds per square inch as read by the gauge psigas opposed to an absolute pressure psia.

Absolute pressure is the pressure of the ambient atmosphere plus whatever the gauge reads. Atmospheric pressure, in turn, is what we feel as a result of the force of all the molecules in the air hitting our body. This pressure at sea level is roughly 15 psi.

As the altitude increases, there are fewer molecules to hit a given area of our skin within a given time. The force per unit area is less, so the pressure decreases. When Kelso slams Duncan's head with his helmet, we can calculate the force of the hit by again using Newton's Second Law.

In this case, Duncan's head and helmet, with a mass of roughly 20 pounds, accelerates to a speed of about 25 feet per second. The collision that causes this takes place in something like a tenth of a second. This corresponds to an average force during the hit of about of pounds, but the instantaneous force can be much higher than the average value.