Download NFL Video Transcript

Science of NFL Football Video Transcripts
Science of NFL Football - Newton's First Law of Motion
LESTER HOLT reporting:
Whether it's a running back breaking through the secondary or a wide receiver on a
foot race for the end zone, most offensive players in the NFL have a single goal in
mind - to get down-field as far and as fast as possible.
ANTONIO FREEMAN (Former NFL Wide Receiver): We're thinking, wow, I've got to
get from A to B within a certain time frame and I can't let this guy throw me off
track. So it's kind of like a chess match at that point in time is to battle to see who's
the toughest.
HOLT: Defenders on the other hand have a different goal - to stand in the way of the
offensive player and stop his forward progress.
HARDY NICKERSON (Former NFL Linebacker): When you are coming in and making
the tackle, you've got to come in and you got to stop him right there on the dime.
HOLT: Who wins this epic battle between the ball carrier and the defender?
Newton's First Law of Motion helps supply some answers.
TONY SCHMITZ (University of Florida): Newton's First Law says that if an object is
at rest it requires an unbalanced force to make it not be at rest or similarly, if an
object is in motion, it tends to stay in motion in a straight line at a constant velocity
unless an unbalanced force acts on it.
HOLT: In football, we see unbalanced forces whenever one player exerts a force on
another and causes him to change his direction and/or speed.
JIM GATES (University of Maryland): So, imagine that a quarterback is just taking
the snap from the center and a lineman gets free from the opposing team and is
coming from the other side and-- when they collide, you can see an unbalanced force
acting on the quarterback, driving him across the field in the direction of the
charging lineman. That's about as unbalanced as it gets.
HOLT: In physics, a player's natural resistance to that unbalanced force is something
called "inertia".
SCHMITZ: On the football field you can think about inertia as being a running back
who is already in motion doesn't want to change the fact that it's already in motion.
So, it's going to take some external unbalanced force, i.e., a defensive player to stop
that running back.
HOLT: Consider former New Orleans Saints running back Deuce McCallister, who at
6-foot-1, 231-pounds used his inertia when running to make him hard to tackle.
SCHMITZ: The size of the player is important to a concept of inertia because higher
mass means more inertia.
HOLT: But a player's mass is different from his weight. Mass is a measure of how
much matter an object has while weight is a measure of how strongly an object's
mass is attracted by gravity.
SCHMITZ: So, for example, a body on earth would have the same mass as that body
on the moon. but it would weigh less on the moon because gravity is less on the
moon than it is on earth.
HOLT: NFL players with more mass have more inertia, and are harder to move off
their path. This concept even works on a quarterback sneak, when a quarterback
uses the combined mass of his entire offensive line to gain a yard or two.
JOEY HARRINGTON (Former NFL Quarterback): If you got an offensive line that can
overpower the defensive line, that's just get on their hip and you just fall, I mean,
you just ride that wave forward.
HOLT: In the NFL, whenever players go head to head it's Newton’s First Law of
Motion that helps determine who will win the battle of the gridiron.
Science of NFL Football - Newton’s Second Law of Motion
LESTER HOLT reporting:
To be an NFL kicker takes more than just nerves of steel and a strong leg. It also
requires help from one of the key laws of physics.
MORTEN ANDERSEN (Former NFL Kicker): It’s easy to say, well, I just kicked the
ball. Well, let’s delve into it. Let’s look at the specifics. What actually happens when
you kick the ball and why does the ball go where you ask it to go – and it is Newton’s
Second Law – Second Law of Motion.
HOLT: The Second Law is one of three laws described in 1687 by Sir Isaac Newton,
who used them to describe how and why objects move.
JIM GATES (University of Maryland): The Second Law says that if you have an object
with a mass that is accelerating – and accelerating means a change in velocity – that
is equal to the amount of force applied to the object. The way we say it with words is
F is equal to MA.
HOLT: This also means that in order for an object, like a football, to accelerate, a
force must be applied. To illustrate Newton's Second Law in kicking, we asked
Morten Andersen, the NFL's all-time scoring leader, to perform his craft in front of a
high-speed Phantom camera. The entire procedure unfolds in less than a secondand-a-half, from snap... to hold... to kick.
ANDERSEN: It’s all about training and rehearsing and doing something over and
over and over again.
HOLT: To reduce the chance of a block, NFL kickers take just three steps to the ball.
The final step is with the plant foot, which provides the stable platform for the kick.
ANDERSEN: I call it the moment of truth, and the moment of truth is basically when
your plant foot hits the ground next to the ball. You’re either in the right position or
the wrong position.
HOLT: The kick, itself, involves the entire leg building the force necessary to launch
the football.
ANDERSEN: It’s a hammer, and when you swing a hammer, you’re thrusting it and
it’s going to be imparting the ball with great velocity.
HOLT: An NFL kicker's foot is in contact with the ball for just 8-one-thousandths of a
second - and in that time, his foot applies up to a ton of force to the ball. This quick,
violent strike is a perfect example of what's known in physics as an "impulse."
SCHMITZ: Impulse is an important concept because there is a finite time over which
the foot is in contact with the ball, and during that time there is a force applied to
the football.
HOLT: An impulse is equal to the force multiplied by the time the force is applied,
represented by delta-T. If force is graphed versus time, it's possible to see how a
larger force or a longer time for the force, supplies a bigger impulse.
GATES: Since impulse is really just the change in momentum and since the ball
doesn’t change it’s mass, we’re really just talking about the change in speed. The
bigger the impulse, the bigger the change in speed, which means the faster the ball is
moving after it leave the kicker’s foot.
HOLT: Ironically, Andersen says the distance of the field goal doesn't change his
approach to the kick, itself.
ANDERSEN: Mentally, you want to look at a fifty plus yarder like a forty yarder with
some room to spare. I think that’s a good way to kind of fool yourself into thinking
it’s a shorter kick.
HOLT: Whether the kick is short or long, Newton's Second Law explains what an
NFL kicker must do to send a football through the uprights.
Science of NFL Football - Newton’s Third Law of Motion
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 say 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.