LESTER HOLT, reporting: Whether it’s a lineman stuffing a running back or a safety colliding with a wide receiver, all NFL defenders have a single-minded goal–to stop the ball carrier. HARDY NICKERSON (Former NFL Player): The object of making a tackle is you want to get the guy down and limit the amount of yards he’s able to gain, especially after contact. HOLT: When a tackle is performed correctly, it’s not just a thing of defensive beauty, it’s also an elegant depiction of Newton’s Third Law of Motion–sometimes called the “action-reaction” law. TONY SCHMITZ (University of Florida): Newton’s Third Law says that each action or force has an equal and opposite reaction. So if I were to push against a body, that body is going to push back against me with an equal and opposite force. HOLT: An important part of Newton’s Third Law is the concept of momentum, which in football is the mass of a player, multiplied by his velocity, represented by the formula P equals MV. NFL players may not know the formula, but they’re keenly aware of the role momentum plays in tackling. NICKERSON: It’s very important to have some speed and momentum as you’re going in to make that tackle. The better you’re able to use that to your advantage, the better you’re able to make contact and get a guy down right away. HOLT: In every collision on the football field, Newton’s Third Law dictates that the total momentum between players must be the same before the collision as it is after the collision. This relationship is referred to as “Conservation of Momentum.” SCHMITZ: The Law of Conservation of Momentum says that the P, the momentum before the collision, is equal to P, the momentum after the collision. HOLT: This law, represented by the formula P-before equals P-after (Pbefore=Pafter) can be illustrated with a simple toy called a “Newton’s Cradle.” SCHMITZ: In this case, we have displaced an initial sphere and when we let it go, it has some momentum–it’s mass times velocity. When it impacts the next sphere that momentum is transferred through the middle three spheres and then passed onto the final sphere and so because it has the same mass, it will move away with the same velocity that the first sphere impacted the middle three spheres. HOLT: The interaction of balls on a Newton’s Cradle can help illustrate what’s known as an “elastic collision, defined as one in which there is no loss of kinetic energy, in the form of heat, sound waves or deformation of the object. On the football field, collisions are typically “inelastic collisions”–because kinetic energy is released, mostly in the form of compression between the players’ bodies and sound waves. JIM GATES (University of Maryland): Inelastic collisions are the rule of the day. We see them all the time in football. That is the energy of motion of two runners after they collide, that energy is dissipated in deforming their bodies, that’s like a spring. So some of the energy of motion went into that compression. You might have heard a loud snap from our pads, some of the energy of our collision was transferred to the energy in the air that you hear. HOLT: While big hits look and sound spectacular, what’s most important in tackling is stopping the ball carrier’s forward progress. NICKERSON: If your pads are underneath his and you are hitting on the upward slope, you direct the energy up and take him back, at the point of contact, hopefully, that’s where the ball stops, play ends. HOLT: Whether a tackle is successful or not, we can be certain that the same force is exerted on both players and the total momentum before and after the collision is the same. For that we have Newton’s Third Law to thank.

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## 28 thoughts on “Newton’s Third Law of Motion – Science of NFL Football”

Informative and entertaining for sure.  TY.
Thinking about how Newton's Third Law is acting on the body and brains of the players makes injury and the concussion issue easier to understand.

2. SIC66SIC66 says:

This series is a pathetic attempt to inject science into this dumb sport..
Violence, like Americans itself…

3. I Ate Eight says:

This didn't apply on 9/11.
🙁

4. DrDress says:

1:10 you think?

5. Jennifer Redstone says:

period 1 group 6: the last law was that how to stop motion from moving anything.

6. Jennifer Redstone says:

3:41

7. Andres Rodriguez says:

those bill's jerseys were fresh though

8. Andrew Veiga says:

This really help with my science project

9. GD Chris/Regret4fall says:

nice info there!

10. Prince Gibbs says:

ITS SO COOWUUUUL

11. iParanormalizer says:

1:05 Or her velocity, I was the only girl on my football team for the past 3 years

12. Snark says:

Bacon

13. 08Covert says:

That taught me a lot about the 3rd law of Newton! Thanks!

14. raghav raj says:

4:12 it was like a Roman Reigns spear😱😱😱😱

15. Derp Guy says:

What’s up stengren class

16. Zachary Rake says:

No more dukes ijhbdcsvjhdbfv,fjhvbefkvljbfvjlkhbvyuyhgbwfevilkhgbwvflkjbndwfvjhk

17. Anime Withered Toy Freddy 1987 says:

Hayo Any peeps from k12 here

18. Linguini Alfredo says:

Who’s watching this for a science thing?

19. levi magee says:

turn up the speed. it will make it go faSTER WITH THE SAME AMOUNT OF INFO edit: sorry for caps

20. Angel Beceril Perez says:

Hi mrs kelly

21. Cat 9 says:

Watt?

22. duhn says:

donavns on insta @stanford

23. Mario Conklin says:

Derpppppppppppppppppppy man

24. Sentinel says:

2:15 spy’s cloak sound and crit sound

25. 8 Ball says:

Momentum is used during football players tackling , the football players tackle someone and then that some force acts on them . They use momentum to be able to knock a player down .

26. BENJAMIN RYAN says:

This video is lit

27. A Sandwich says:

The science of NFL Football: Newton’s Third Law answer sheet
7. Action-Reaction Law
8. P=mv
9. Yes

28. IamJAG_GG says:

OwO