Physics of Football

Physics of Football


Weber rolling out. And he’s gonna throw deep for Decker. What a grab! Touchdown, Minnesota! Looks like that hit on Golden Gopher wide
receiver Eric Decker didn’t feel too good. Decker shaken up as he got hammered. The blast from Cal safety Sean Cattouse
had enough force to cut Decker’s jaw open. And while Decker clearly was uncomfortable after
the hit, the Gopher athletic staff was able to stitch him up so he could
head back into the game, which is amazing considering
the force his body withstood. Just to hold on to that ball is a testament
to the hand strength of Eric Decker. But hold on a minute, just how
much force did Decker endure? How hard was that hit? How many Gs did Decker experience
during that hit? To find that answer we took University of
Minnesota Physics professor Dan Dahlberg out to the TCF Bank Stadium field to break down the science behind Decker’s
amazing touchdown catch. Knowing the time and the
distance where he landed, I can now calculate what that velocity was. To find those numbers, Dahlberg
first had to study some film. Using the game footage, he was able to break
down the play in several different ways, coming up with estimated speeds
of Decker, Cattouse, the impact and the time it took for
the both players to land. Next comes the math. And so that acceleration that he was
experiencing was 345 feet per second squared. Knowing factors like Decker’s speed in the
40-yard dash and the time it took for him to travel between the 10 and 5 yard lines,
which was determined by watching the video, Dahlberg was able to come up with an equation
that allowed him the estimate the amount of G force exerted on Decker’s
body during the brief impact. And the key to doing that was determining
the distance between where Decker was hit to where he landed on the ground. And so in terms of Gs I’m going to take
this 345 feet per second squared and divide that by the acceleration due to gravity,
which is 32 feet per second squared, and when we do this we find that
his acceleration was 10.7 Gs. To be precise, Dahlberg says Decker
felt 10.78 Gs of force during the hit. Now that 345 feet per second squared divided by
32 feet per second squared, which is the force of one G, gravity, and that’s how you get 10.78. 10.78 Gs of force that Decker
suddenly felt during that hit. Now, that’s a pretty big number. I found one report online where Navy carrier
pilots undergo acceleration of about three Gs where they’re taking off from the
catapult assist on the flight. In car wrecks it looks like you
could have as much as 40 Gs. To give you some idea, this 10.7 Gs, if Decker
weighs say 200 pounds, right at that point, during that collision, he’s
weighing more than a ton. Standing on the field, with no other forces
factored in, Eric Decker weighs 220 pounds. For a brief moment during the impact,
Decker had 10.78 Gs thrusting him. 10.78 times 220 is more than 2,30,
which means for that brief impact, Decker felt like he weighed 2,300 pounds. That’s more than three and a half
times the force Navy pilots feel when they’re being catapulted
off an aircraft carrier’s deck. And yeah… Following the review, the ruling on the
field of touchdown has been confirmed. — Decker held on for the touchdown.

About the Author: Garret Beatty

100 Comments

  1. Saying from a student in highschool, I could of figured this out, though for some reason my physics class does m/s^ instead of ft/s^, so yeah.

  2. give me some feedback here but i think who give a crap about physics in football you run at the guy and you tackle him haha

  3. ok everyone this might have been a touchdown, and this might not of been a touchdown; however, the ruling on the field was a touchdown. the ref kept it a TD after the review because there wasnt indisputable evidence of whether it was a TD or not. there you go, problem solved.

  4. doesnt matter, as long as one part of the body crosses the plane by a ball carrier with posession. its a touchdown. remember that mike vick play from a few years ago

  5. this is not all true . his comin up with all these big numbers and saying that he took 10ft/s2 and shit wen with all the paddin the footballers are wearin it atleast took 50 % of the impact ! pussy stuff 😛

  6. His speed down the field shouldn't really factor in because it looks like he slowed down at the end there in order to get ready to catch the ball. There's no way he was going as fast as he was down the field when he turned to get the ball, turn back around to go for the goal, etc.

  7. 10.78 Gs is well within the realm that the human body can handle. Fighter pilots in say an F-16 routinely and for periods of 10-20 seconds hit 9Gs in ghigh speed tight turns. I played football through college and can tell you, it isn't always the impact that hurts…alot of times it is the hardness of the helmet hitting your hip bone or something like that, or getting stepped on by cleats! cool vid

  8. no, football can refer to many different sports depending on where you live

    in Australia, football can mean AFL so in Australia we call NFL "Gridion" or just NFL.

    in England football can mean Soccer

  9. Actually there have been some rugby players in the nfl. The Jets had a kicker that played rugby a few years ago. That man tackled unlike most kickers. He was a good tackler too.

  10. Why is American and Australian football called football? Ask rugby players because it came from rugby football. They're both modified versions of the sports, they're both high different thougj

  11. We talk about sport too!!
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  12. 1:28 – 1:30 "three hundred and fourty five"
    I would expect a physics teacher to properly word a number, it's "three hundred fourty five", there is no and. An 'and' represents a decimal point, so in actuality he is saying 300.45.
    I know this seems like knit-picking, but that's like a food expert confusing a teaspoon and tablespoon measurement.

  13. @ itsMInuteMaid
    You are wrong. Actually "three hundred and forty five" is grammatically correct in proper English(Britain). Please don't correct a physics professor who has probably studied much longer than you.

  14. He's a professor of physics, IN THE UNITED STATES. Even if what you say is true, that, that is the proper Britian wording, that is NOT the case here. Just as a word or phrase my be grammatically correct in Mexican Spanish, it may not be in Spain Spanish. Language evolves, just like everything else, and the wording for numbers has evolved to how I explained it. I wouldn't be suprised if YOU are wrong, and even in Britian, using 'and' in the middle of a whole number is incorrect.

  15. Furthermore, in proving my point, you wouldn't say "fourty and nine", that would be incorrect, you would say (as we all do), "fourty nine". You do NOT say 'and', when stating a whole number, again, 'and', denotes a decimal point. I'm quite sure you're wrong, even about British English.

  16. WHAT?! No, you don't say 'point'. For example, when you say, 'two hundred thirty-three dollars AND forty-five cents' $233.45 (see hoe the and goes where the decimal goes). You wouldn't say 'two hundred and thirty-three dollars and forty-five cents', that would be $200.33.45. When do you say 'point'?

  17. @itsMinuteMaid you're confusing money with math – two different languages. For money you say "Three dollars AND forty five cents" because you are talking dollars and cents – two different values (dollars AND cents). For numbers in math, since the labels are the same – in this case feet per second squared, you have three hundred and an additional forty five. Same labels, therefore and is allowable – but in math context. True, you cant write it like that on a check, but its allowable.

  18. @itsMinuteMaid What is the past tense of the verb "hang"?
    It is hanged, not hung. There are many ways in which English grammar is counterintuitive. And as titanwr mentioned, math should not be confused with the proper way of writing checks.
    Also your argument of British grammar being unacceptable in the USA is foolish. British English is the way the rest of the world is taught English, and is the world language.

    If you are still not convinced, you can try to research it.

  19. theres a misscalculation, i suggest to make a review. those calculations were made assuming velocities in oposite directions, there's an angle that wasn't considered…the force is less than 5 G's

  20. 10.78 gs is precise but it may lack accuracy since the prof could only estimate the distance with an uncertainty of half a foot from the videos. The announcer didn't take very many science classes, because he grabs onto 10.78, although it isn't meaningful if the actual force differs by say half a g

  21. It was definately a touchdown. His foot toe tapped at the 1/2 yard line, well in bounds. You only need 1 foot in college ball. The ball does not have to cross the goal line between the pylons, and he doesn't land out of bounds until he was 2 yards past the goal line. He maintained possession through his landing. It's a TD

    By NFL rules, it wouldn't be a touchdown, but that is irrelevant.

  22. @solgearx

    Typical American sport, only speed and strength, no intelligence or technique whatsoever, except quarterbacks. Every player needs to be doing only one thing during a whole career, but still that's the only way for those dumbasses(most of them are) to finish college.

  23. Tell me about it.

    I just hate how they make this seem like this is soooo intricately complicated and deep in scientific analysis lol.

  24. He managed to get one foot down in bounds at 0:23 so he was "in" then, as long as the football crosses the plane of the end zone ( touch down area) before his knee hits the ground, he scores.

  25. @manurulzz5 Why don't you do it? I won't bother. i trust him. I could go thorugh his calculations and simply put the divisions into my calculator and see if he's right. but his formula's checks out. So I won't bother no reason questinoning a professor in most cases. Id estimate it to something around what he got.

  26. The game is set up in the imperial system.

    I know metric and imperial. It's just a cultural aspect that we still value.

    No need to be a pretentious dick or anything.

  27. Most people do not care about the physics of football, hits and impacts are what they are. I don't need a bunch of numbers and useless information to know how hard a player was hit.

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