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Dustin Valkema

It’s Football time!

        On February 3rd of this year two great Football teams will undergo a grueling battle to win the title of the Nations best team this year, better known as the Super Bowl by the NFL and fans. What many people may not know or realize is that football, at its core, is almost entirely wrapped around the laws and principles of physics. In saying that, it’s not crazy to assume that the team that can understand, execute and react these principles will become this years Super Bowl champs. Now, I do understand that there are many unpredictable occurrences, psychological factors that play into games like this and rules that each team needs to abide by so for the sake of this discussion we’ll stay out of the politics and focus on a couple examples of how physics is used throughout the sport itself. I will also look to generalize these examples to keep an unbiased focus from each team, not that I’m rooting for the Ravens or anything.

Lets dive in and take a look at how the quarterback and how he uses his knowledge of physics to calculate where and how he will pass the ball. We know that an object that is launched in any given path is called projectile motion, and would be initiated when the he throws the ball. We have also come to understand that the arc or parabola is the curved path that the ball follows from its initial point of release, to the point of impact whether it is the receiver, or the ground when acted upon by the force of gravity. Now before the quarterback makes his decision on where and how to pass the ball he instantaneously gauges the elements at play and then uses his knowledge of physics to calculate the pass, which through years of training and experience has become second nature.

Given our understanding of the parabola or path that the ball will take once it leaves the quarterback’s hand, there are three key factors that are a vital influence the path of the ball at this point. The first is the angle at which the ball is launched. We know that at 45 degrees is the sweet spot for reaching a maximum distance with the force of gravity acting as the force pulling down on the ball and decreasing it’s vertical speed in mid air.

The second factor is the velocity or speed at which the ball is thrown. We know that the velocity is based on the speed and angle of direction that an object travels, so having this knowledge the quarterback is able to judge how much force to put behind the ball as he’s throwing. In essence, the more distance between he and the receiver, the greater the force he would need to put on the ball, depending on the angle at which it leaves his hand.

Lastly he will have to make sure that the positioning of the ball in his hand and snap of the wrist is correct to form a perfect spiral when the ball is thrown. Having a perfect horizontal spin on the ball will reduce the amount of air resistance, allowing it to travel further and stay in the air longer, thus giving the reviver ample time to any quick adjustments that he needs to in order to pull it in. Understanding how gravity affects the vertical speed of the ball is crucial when passing deep or at all for that matter. Any slight miscalculation made by the Quarterback can lead to an incomplete pass or interception if the receiver isn’t able to make the proper adjustments on his end to make up for it.

As the second example of how football and physics are related we’ll take a look at the running and tackling aspect of the game. We know that both a running back and linebacker can hit hard, but when they meet, the outcome of who’s left standing is all about the science of the hit.

Have you ever noticed how both the linebackers and running backs are pushed back off of the line of scrimmage? This is so they can have room to accelerate from their position of rest and reach a high velocity before meeting their opponent, giving them better momentum in preparing for the hit. Since momentum is based on mass and velocity each player, regardless of size can have the same momentum and bounce straight off of each other if they’re countering each perfectly, which isn’t often the case. We often see one of the two falling to the ground or the other being tackled. This is because acceleration and momentum aren’t the only elements that feed into the linebacker making the tackle or the running back plowing the linebacker over.

One of the bigger elements in this part of the game is the subjects’ center of mass, better known to many as their center of gravity. This is vital point in the body and is generally right above the hips on most males. Your center of gravity is the point at which your body will rotate the easiest creating torque, thus leaving you vulnerable to losing your balance if your center of gravity is too high. Now torque is the product of distance from the rotation axis (center of mass) and force applied in which this case would be one player contacting the other. When a player has a center of gravity is low his potential for torque is also low. This is why every football coach pushes keeping a low and crouched center of gravity as you run, move, block and collide. Combining a low center of gravity with momentum will generally give you the upper hand when meeting an opponent, which is also why both offense and defensive players are trained to run through a collision and not stop on impact. One player must have a lower center of gravity and higher, continued momentum, if he expects to take the opposing player out without losing balance. With all of this being said the key principle behind running, tackling and hitting is to have a lower center of gravity, and to keep those feet churning through your opponent. It could be the difference between a breath taking tackle or a game-winning touchdown!

The topics covered here are only a small portion in how physics are applied in Football, and only a sliver of examples given. Physical Science is applied in every sport in one way or another, and understanding how physics is applied can give a much better understanding of what’s really happening as you watch your sport of choice. And to those of you that get hounded by their significant other for watching too much TV when it comes to sports, just tell them you’re studying the physics of the game and explain some of the principles given here. Chances are they’ll either walk away bored of listening to you talk, or you won’t get off that easy. Either way it’s worth the 50/50 gamble right? Below you’ll find a link to a pretty cool video of how Ray Lewis competes with a battering rams power to plow through a door using physics, check it out!

http://www.youtube.com/watch?v=sBVCyXdPevY&feature=player_embedded

Welding. (n.d.). The Physics of Football. In physics of sport. Retrieved January 24, 2013, from http://physics-of-sport.net/football.html.

Echo Romeo. (November 24, 2010). The Physics of Football. In physics central. Retrieved January 24, 2013, from http://physicsbuzz.physicscentral.com/2010/11/physics-of-football.html?m=1.

Section 5

Andrea Bain

Physics Follies: or How Dumb do I Look?

By Andrea Bain

Movies are full of physics impossibilities. If the world worked like Hollywood often portrays it, we would have exploding cars in every wreck, people flying through the air after being shot, people jumping through glass windows willy-nilly and fires blazing from cigarettes tossed into gasoline puddles.  “What’s this?” you say. “These are physics fails?”  These and many more are used in the movies so often that we have come to believe them.

Take the car instantly exploding on impact scenario. A car’s gas tank is usually in the back of the car. That coupled with the fact that most fires usually start in the engine compartment means that instant explosions on impact just don’t make sense.  People are so convinced that a car will blow immediately that there have been many preventable injuries from people yanking a person out of a burning car when they could have taken a bit more time to asses the persons injuries. The fact is, that gasoline itself is much less flammable than the fumes evaporating from it.

All of which leads me to the lighting gasoline puddles with a lit cigarette scenario.  We all love a great revenge scene. In Payback starring Mel Gibson, his character, Porter, starts a gas leak in a car occupied by his antagonists and then lets the gas follow gravity.  It flows away from the car to a safe distance for Porter to avoid injury when the car blows. He waits for just the right moment and flicks his light cigarette into the pooling gasoline, which ignites it, and the flames rush toward the car resulting in a flashy explosion.  The problem with this physics violation is that a cigarette dropped in gasoline is usually immediately doused. Again, the liquid in gasoline is not what burns. It is the fumes. So could a cigarette light gasoline? Yes, unequivocally.  But it would take a situation where the cigarette would contact the fumes instead of the liquid.

Another physics violation is when a person is shot and as a result they go flying backward. Bullets are streamlined little projectiles. They have a lot of kinetic energy but it’s concentrated on such a small area that it doesn’t transfer that energy to the surface of a human it hits. Instead, it penetrates because it lacks the momentum to move an object as large as a person.  If the person were wearing a bulletproof vest however, they would have the bulk of that energy hit the surface instead of it expending its energy by penetration. Even then, however, it won’t make you fly across a room. It will leave a terrific bruise and broken ribs since that energy does have to go somewhere.

Finally, when you dive through a window, it does not look cool unless you’re in the movies. In reality, it would make you a bloody and possibly dead mess. Due to the weight of the glass and the inertia, the shards of broken glass tend to stay in place and then fall straight downward, unless you are unlucky enough to be in the way. Then you push the shards with your momentum. Having handled a broken glass, I know how easily it is to get cut. Add razor sharp edges to the collision caused by you jumping through the window and you get lacerations and severing of important parts you probably don’t want to lose.

So the next movie you see that has an exciting action sequence that totally blows the laws of physics, try not to overthink it while you’re in the theatre. After all, if the scene is convincing, and the special effects are awesome, that makes it have a cool factor that can kind of outweighs the bad physics. But as with anything, you have to know the laws in order to successfully break them.

References

Rogers, T. (December 1. 2009). Movie Physics and Mojo. In Insultingly Stupid Movie                                                                      Physics. Retrieved January 27, 2013, from http://www.intuitor.com/moviephysics/.

Unknown. (November 18, 1997). Flammable & Combustible Liquids – Hazards. In Canadian Centre for Occupational Health and Safety. Retrieved January 27, 2013, from http://www.ccohs.ca/oshanswers/chemicals/flammable/flam.html.

Payback (1999). [film] Brian Helgeland .

Tvtropes.org (n.d.). Blown Across the Room – Television Tropes & Idioms. [online] Retrieved from: http://tvtropes.org/pmwiki/pmwiki.php/Main/BlownAcrossTheRoom [Accessed: 27 Jan 2013].

Section 6

James “JT” Torres

Growing up as a suburban child in the early nineties, I spent my fair share of time in arcades.  Although I was usually there to partake in video games that weren’t available on home consoles, I also spent quite a few (rolls of) quarters on pinball.  I always loved watching the ball bounce around the playing field and I always thought the game was just about timing.  Little did I know at the time that a working knowledge of physics influences the game as much as a player’s hand-eye coordination.

One would think that the only input the player contributes to the game would be when and if they hit the buttons that activate the flippers, how hard they move the machine (tilting) and, in older models, how far back they pulled the plunger to launch the ball.  Anyone can tell you that, generally speaking, the more you practice at something, the better you become at it.  Besides relying on twitch reflexes, a pinball wizard needs to learn the physics of the machine.

The first true pinball game was 1947’s Humpty Dumpty, which incorporated flippers for the first time.  However, unlike modern machines, Humpty Dumpty had 6 flippers that faced outward.  It wasn’t until 1950 when a game called Spot Bowler put the flippers facing inward toward bottom of the playing field.  Even without a degree in physics, a good player will notice and remember how the balls bounce off the flippers at different angles.  The flipper will then send the ball back up onto the playing field dependent on how forceful the player presses the buttons controlling the flippers, demonstrating a conservation of energy.

The playing field is angled at a 6-7 degree angle to allow the ball to be influenced by gravity. Besides keeping the ball from becoming stuck, this forces the player to do something that humans always strive to do: to oppose gravity.  Although it’s not on a grand of a scale as space flight, the name of the game is to keep that ball from obeying one of the primary laws of physics.

The tilt sensor in a pinball game was an invention that was created to decrease cheating on the machines as well as to circumvent damages to the machine.  The first tilt sensor was called a “stool pigeon”, and was created by Harry Williams of Williams Manufacturing.  This was nothing more than a ball on a pedestal that would fall and hit a metal ring when a player would push the machine hard enough.  Although the tilt mechanism has evolved over the years, it still relies on the same concept.

In older pinball machines, the player pulls back on a plunger to launch the ball.   On a normal table, a standard steel ball measuring 1 & 1/16th inches in diameter can reach speeds of 145 kph.  The plunger allows the player to deploy the ball at different velocities, to either give them control of their launch speed or to sometimes hit certain bonuses known as “skill shots”.  Objects on the playing field can also influence the ball.  The ball can bounce off of and be launched out of various objects and special areas.

If a player wants to receive a high score, it would be best to learn the “feel” of a particular machine.  A skilled player will take into account how the ball moves, how the force exerted onto the flipper buttons translates onto the field and even how hard the machine is shoved.  Even though some machines are now digital, the physics behind pinball remain the same.  Next time you play pinball, hopefully you’ll remember that timing isn’t everything.

References

Porges, S. (2008, August 5). Top 8 most innovative pinball machines of all time read more: Top 8 most innovative pinball machines of all time Popular Mechanics, Retrieved from

http://www.popularmechanics.com/technology/gadgets/toys/4276614

Brannan, S. (2001, May 8). How pinball machines work. howstuffworks.com. Retrieved from http://www.physics.org/explorelink.asp?id=118&q=site¤tpage=8&age=0&knowledge=0&item=76

(n.a.). (2004-2012). The internet pinball machine database glossary. Retrieved from         http://www.ipdb.org/glossary.php

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