As we gather around the TV this Sunday with friends and family to watch one of the biggest sporting events of the year, wolf down chicken wings and nachos, sing along to the half-time show and chuckle at million dollar commercials, there’s another thing that we can do as well – discuss the science behind all that football!
We are currently covering the unit on impulse and momentum in our Physics class and there are multiple examples of its application in our everyday life. For instance, the role of safety belts in cars help save our lives in the event of a collision by extending the time of impact. This subsequently lowers the net force experienced by the driver when the car comes to a sudden stop. It is also the same reason why we bend our knees when we land from a jump or have the extra cushion of air in our pair of Nike Air Max sneakers.
During a play when one player gets tackled by another player, the change in momentum experienced by both players are the same, but they are exerted in opposite directions (think Newton’s Third Law of Motion where every action has an equal and opposite reaction). The amount of momentum a player has depends on two things – his mass and velocity. The more momentum something has, the harder it is for you to make it stop. If a less massive player (Ted Ginn, Jr. at 185 lbs or Lorenzo Doss at 187 lbs) intends to tackle and drop a more massive player (Louis Vasques of the Denver Broncos weighing in at 335 lbs or Chris Scott of the Panthers at a whopping 340 lbs) , he would need to make up for the mass difference by increasing his velocity proportionally. (FYI, the average football player in the NFL weighs about 225 lbs.)
In addition to the player’s change in velocities, the force of impact on each player is also extremely high when the collision happens in a small amount of time. The Impulse-Momentum Theorem tells us that the average force increases as the time of impact decreases when the change in momentum is constant. This means that when a player gets hit, that force can be a ton of hurt! At 5 ft. 11 in. and 199 pounds, Marcus Trufant is an average-size NFL defensive back (DB). Those stats don't stand out in a league where more than 500 players weigh 300-plus pounds, but a DB’s mass combined with his speed -- on average, 4.56 seconds for the 40-yard dash -- can produce up to 1600 pounds of tackling force, according to Timothy Gay, a physics professor at the University of Nebraska and author of The Physics of Football.
With all that force, how can anybody handle that kind of hit? The answer lies in the distribution of the energy throughout a player’s equipment, which include the shoulder pads and helmets. These are designed similarly to the concept of “crumple zones” in cars which absorb the impact of a collision to protect the passengers – science in action once again.
There are many other examples of science in action when watching the big game on Sunday -whether to kick or not to kick that field goal or if an under inflated football gives a team an unfair advantage. Whatever it may be, it’s a win for everyone if we can apply what we learned in science class on the football field. Go Broncos!