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The Simpsons Physics (1): Pianos and Angular Momentum

So The Simpsons is one of my favorite shows of all time for it's hilarious characters and plots, and interesting story. Now cartoons are not always known for their strict following of the laws of physics (because sometimes it's just funny how fake it can be), but this particular scene I am about to analyze does a pretty good job of demonstrating a key concept: conservation of angular momentum. In this scene, a student (Ralph) is in great peril, and so Principle Skinner attempts to save him by sending a message, however, this escalates the situation as it leads to a giant crate at the docks dropping grand piano's. First, lets analyze the physics of these falling pianos. The crate appears to be tilted up at an angle of 45 degrees with the horizontal, meaning that the piano's are accelerating down the crate at about 6 m/s/s (assuming some friction). However, what is comical is that there appears to be an infinite supply of pianos as we see 20 something pianos fall out of the too small crate. Assuming a max amount of 20 pianos, and each piano at 5443 kg, the tension in the rope supporting the crate would have to be 1,100,000 N!!!  Lastly, the Principle demonstrates conservation of angular momentum by running in a circular path around the crate. The crate then reacts and moves in the opposite direction. Because Skinner has an angular momentum in the clockwise direction, by conservation of momentum, the crate moves in a counterclockwise direction. This is also a representation of Newton's third law that for every force there is an equal and opposite reactionary force. Off course, Skinner's mass is so puny compared to the crates, it would not pin nearly as fast, but nonetheless, still hilarious.

The Butterfly Effect

So i was watching a YouTube video and I came across an interesting concept. This gets into theoretical physics with parallel universes and stuff. So basically the Butterfly Effect states that the smallest action, such as the flap of a butterfly's wings can change the outcome of something in the world thousands of miles away. This implies then that if a person was able to go back in time, and they make one difference, they could change the future in millions of different ways. This leads me to think that there are thousands of parallel universes, some very different from ours and some virtually the same. When a choice is said to be made, both of those choices are made, kinda similar to the Schrodinger's Cat problem. As result, there are trillions upon trillions of different combinations of choices and events, each creating a different universe. Just something to think about.

The Bottle Flip

In this blog I will write about the internet phenomenon known as the water bottle flip. This action gained popularity in high schools and colleges around the world, and national talk shows, and even in the NBA! It's time to analyze the physics behind the so appealing flip. First of all, most of the bottles being flipped have a lower amount of water in them. They are certainly not full, about 1/3 to 2/5 full to be exact. This lowers the center of gravity, and therefore makes it easier to land the bottle. A higher center of gravity in a full water bottle would make the bottle want to tip over as the force of gravity is stronger and further from the surface. Secondly, when you flip the water bottle, based on angular momentum, the bottle will continue to rotate as result of inertia. However, the nonuniform water at the bottom of the bottle has a resistive net force down, and therefore a net torque that will cause the bottle to decelerate. As result, the bottle slows down when it reaches its upright position and has a great chance of landing opposed to a full bottle of water where the force of gravity is uniformly distributed. Finally, I will show you the video that started this whole bottle phenomenon. It is intense.

Tennis

As basketball season has come to a close, it makes way for tennis for me, and there is plenty of physics in tennis.  First off, the tennis racket itself has engineering to allow the ball to fly with maximum velocity. Many cords are woven in the foundation of the racket, the strings have a strong tension in them and as result the hard tension allows for a ball to bounce of the racket and change direction. The rackets tensions are rated in force, specifically pounds (maybe newtons in Europe). anyway that's just a little bit on tennis. There is plenty more such as kinematics and momentum, but that's for another blog.

String Theory

So recently in physics class, we were talking about relativity and theoretical physics, and String Theory came up. Naturally, I was intrigued by this topic, and so I researched the topic a bit. Basically here is the run down: In physics, particles can be replaced by one dimension things called "Strings." These strings propagate through space and time to interact with each other. A string is basically a quantum particle that carries a gravitational force, and therefore is Quantum gravity. Quantum gravity uses Einstein's theory of gravity using quantum mechanics. Furthermore, I watched a video on string theory where it related the creation and fission of different universes to string theory. the video compared a universe to a bubble, and we are tiny, tiny bugs on this giant bubble. A universe could form in two different ways: through either the collision of two different universes forming a new one, or the fission of one universe into two. The forming of our universe is what we have come to know as the Big Bang. This implies that if there is a multiverse of universes, we could travel to different ones. In order to accomplish this task, theoretically, we would need to use a wormhole to take a shortcut to another universe. A great example of a wormhole is to bend a piece of paper and stick a pencil through it. A wormhole is similar in that it bends space and time to create a shortcut.

Steph Curry's Jump Shot

Stephen Curry, a professional basketball player on the Golden State Warriors, is no doubt one of the greatest shooters of all time. Naturally, there is plenty of physics behind his sweet stroke. In this blog I will analyze different components of physics that relate to his game with the help from ESPN's Sports Science video on him.  First off, Stephen Curry runs down the court at 10 mph (about 4.4 m/s) and can stop on a dime in approximately 1/3 of a second. This the implies that the deceleration of Curry when he gets set for a shot is 13.333 m/s/s. Because Curry has 87 kg of mass, a 1160 N force is required for Curry to make this stop. This means that this force is being applied to Curry's shoes as a force of friction by the ground and onto his legs. Furthermore, Curry shoots the ball, on average, at an angle of 55 degrees. Opposed to an average trajectory of 45 degrees by a taller player, Curry's higher arcing shot allows for him to shoot over taller defenders. Furthermore, his ball has a smaller initial horizontal velocity because it is in the air longer. Lastly, this higher arc increases the area in which the ball can go in by 19%!  Lastly, Curry's release is wicked fast. On average the ball leaves his hand in .4s. This is the same time it takes the ball to undergo one full rotation, which implies the angular speed of the ball is 15.7 rad/s. To give a comparison, the average release time is .54s; Curry's crazy fast release is what makes him great.

Simpsons Physics 3: Up, Chuck, and Away

I recall an episode of the Simpsons where Homer and Bart go in a "Zero Gravity Ride" on a jet. In the show, the way the ride works is the jet flies very high above the altitude of Earthy, then when it reaches maximum altitude, does a nose dive towards the surface of the Earth. If we analyze the physics behind this, we can understand that because the jet is in free fall, Bart and Homer are in free fall, and therefore its like "0 Gravity." In reality, there is still a gravitational force acting on them, but it feels like there isn't because of free fall, and the jet falls at the same rate as the things inside. This is the exact same concept of a space shuttle in orbit. When astronauts are in orbit, they aren't really in a place with Zero Gravity. They are actually in constant free fall around the Earth.  Furthermore, we can analyze the motion and actions Bart and Homer make when in free fall. one thing they do it float, but in order to move themselves a net force needs to act on them. By pushing their legs off the wall, a normal force is exerted on them and they can thus accelerate in the x direction until hitting the wall across them. Also, at one point they have a race by burping. Because burping releases gas from the system, an equal and opposite force pushes Homer and Bart in the opposite direction. This force is of course exaggerated for the purposes of the show, but the idea behind it is correct, similar to using a fire extinguisher on a rolling chair to move. Now indulge yourself in this comedic video of the scene.

Simpsons Physics 2: Springfield Gorge

In an earlier episode of what came to be an instant classic, Homer Simpson accidentally attempts to jump over the "Springfield Gorge" (most likely the Simpson's version of the Grand Canyon). Anyway, while this scene is extremely funny, there some  inconsistencies to laws of physics. In this blog I am going to point out a few. First off, when Homer first goes off into the air, he stays at the apex of his motion for about 3-4 seconds while only having a horizontal velocity. In fact, it almost seems as if Homer's vertical velocity seems to oscillate up and down. Of course, any physics student will tell you that this is incorrect, force there should be a net force of the force of gravity acting on Homer, and therefore he should have been accelerating downward (not in vertical equilibrium). Furthermore, when we get a wide-shot of Homer, once he realizes he is not going to make the jump, the acceleration due to gravity acting on him seems to increase exponentially; it certainly was not a constant acceleration and while this makes for hilarious television, it does not meet real life physical standards. Lastly, Homer actually falls down the cliff twice, and the force of the gorge and rocks acting on his body would surely be enough to kill him, but of course he is Homer Simpson, and when he wants to, he gets to decide the laws of physics.

Rotation of a Clock

A clock is a very helpful invention and there is plenty of physics behind it. Today I am going to analyze he rotational motion behind a clock.  First off, when any hand completes one revelution, whether it means a minute, an hour, or 12 hours, the angular displacement is 2(pi) radians or 360°. This of course allows us to find the angular velocity (w). If we are talking about an ideal clock that rotates at a constant rate, we can determine that the second hand travels pi/30 rad/s. Next, the minute hand travels pi/1800 rad/s. Lastly, the hour hand travels pi/108000 rad/s. The angular velocity will be the same on every clock, but the linear speed of the outermost part will be greater the larger the clock.  Now this gets a little more complicated if we have a clock that ticks (which a lot do). The second hand does not travel at a constant velocity, rather it accelerates then decelerates, every time it travels one notch (pi/30) rad. On a certain watch I have, it takes about .3s for the hand to move one tick, meaning he acceleration and deceleration are about 9.3 and -9.3 rad/s/s. Clearly clocks are very complex but have some cool physics.

Physics of the Bow and Arrow

Our latest unit in gym class is archery and it has me thinking quite a bit about the physics behind a bow and arrow.  For example, first of a bow is composed of a frame of some material that can stretch. Next a stein string like material is tied to each end. The tighter the string, the higher the tension. A bow with a higher tension applies a greater force and therefore the impulse delerviered to the arrow is greater, (which of course is change in momentum). Energy is transferred into the arrow which hits a target or deer etc. other factors that come into play include air resistance and the force of gravity.  Lastly, there are bows with pulleys that redistribute the force, making it easier to pull back the arrow, but still have a great force applied. The compound bow was invented by a man with the last name Bear. Thanks Bear!

Physics of Hockey

In gym class we are currently in the Floor Hockey unit, and it has me thinking about all the physics behind hockey, both ice and floor hockey. First of all, in ice hockey, skating is an important feature. The coefficient of kinetic friction between skates and the ice is very, very low, it almost acts as a friction less surface. As result, when hockey players exert a force on the ground to accelerate themselves forward, the only way to stop in time is to turn the skates sideways and let the sharp skates dig in the ice to create a strong force of friction. For similar reasons, when a puck is shot, it will not slow down unless acted on by another force (usually another player, or the wall). Finally, why do goalies where so much padding? The reason is because a goalie is expected to save shots fired at them up to 150 mph. If they stop it, it will of coarse result in a very high impulse over a short period of time and therefore deliver a strong force to the goalie. For protection, pads are worn to decrease the change in momentum of the puck.

Physics of Dunking

There is plenty of physics when it comes to playing basketball, from shooting a three pointer to dunking. In this blog I will assess the physics behind dunking a basketball.  First off, you probably have to be a decent height, the shorter you are, the more force your legs will need to provide. Having a high vertical is the most important thing, however, for example Michael Jordan, one of the greatest dunkers of all time, had a 40 inch (1m) vertical. Now the initial velocity needed to reach this height (with the acceleration due to gravity at 10 m/s) is 4.47 m/s. Assuming the force your legs provide is over a time of .5 seconds, the acceleration is about 9 m/s. Given that Jordan was 100 kg, the normal force provided by the ground (created by his legs) is approximately 900 N! Clearly, there is some strong force required to jump and dunk, which is why you should never skip leg day, but more physics behind leg day another day.

Physics of a Trampoline

A very fun activity to do on a sunny day is jump on a trampoline. Fun for all ages, a trampoline makes it easy to get major air. What exactly is behind this mechanism of a trampoline flinging a person into the air? Well let's talk physics in terms of energy. Let's say that our reference level is where one stands on the trampoline. As soon as a person stands on a trampoline the webbing is stretched and sinks down to equilibrium. This is similar to our lab experiment of placing a mass on a vertical hanging spring. Now once a person stretches below equilibrium (by pressing down a force and/or jumping up) the fun begins. A person has a potential energy at the top of their jump, and this is converted into kinetic energy as they move, which is then turned into spring potential energy, when a person stretches below equilibrium level.  This idealogy is the basic physical concept of a trampoline. With this knowledge a person can incorporate cool and crazy tricks to do on a trampoline.

Physics in Rock Climbing

So it has been break, and on a rainy day without school what can you do (other than read the physics textbook)? Go rock climbing. That's what I did recently and there is plenty of physics in it. For starters, when a person climbs up a wall, they are doing work against the force of gravity, or the gravitational field. Therefore potential energy is gained he higher one goes up. Now energy exerted is of course lost with sound and friction between rocks and hands.  Furthermore, there are plenty of safety measures when rock climbing in a licsensed facility. Many places have people strapped to ropes in case of a fall, and to get down. Simply put, the rope is suspended over a pulley, with a person climbing on one end, and another person on the ground. The pulley helps redistribute the weight of the climbing. Once the person is ready to come down, the rope is pulled tight for the person climbing to be suspended in air. Therefore, the tension in the rope is approximately the weight of the person.

Physics at the Park

Everyone loves going to the amusement park; a local favorite is seabreeze. When we are little, we enjoy the ride, and have a good time. However, as I have grown more and more into my physics career, going to the amusement park is not quite that simple for there is physics all around the park. In fact, if it weren't for human accomplishments in physics, there would be no park!         The first ride I thought about this was the musical express. On this ride, people sit in carts on a circle and the entire ride rotates over and over again, until the ride is going a very fast velocity. One of the warnings of the ride is for smaller passengers to sit on the inside. Why is this? Cause the smaller passenger would get squashed! There is a centripetal force with this ride, based on the equation a=v^2/r. The ride gets to a point so fast that the friction of the seat is overcome and th people squish together!     Secondly the Jack Rabbit is a classic example of conservation of energy (kinda). Based on the conservation of energy, when the ride is at its highest point, the potential energy will be converted into kinetic energy, and therefore the ride cannot reach a higher point without being acted on by an outside force. Unfortunately the world is imperfect and there are outside forces, like friction! The Jackrabbit has three humps, and each hump is lower than the prior, this is because friction steals energy, and therefore it cannot reach a higher point. All in all, physics makes our lives a little bit more complicated because we can no longer enjoy the ride without thinking.

Phootball Physics

All sports have a lot of physics to them, but one sport in particular I have noticed to demonstrate principles of physics is football. Watching the NFL, the Minnesota Vikings are my favorite team, and though they had a great 5-0 start, ever since the bye week they have been slipping. Here's the physics behind their struggles.  The pass rush defense is weak. Viking blockers apply a force to the pass rushers, however, the pass rushers force is greater and able to overcome the resisting force. This causes a net force in the direction towards QB Sam Bradford, and as result he gets sacked. Furthermore, in the red zone, Bradfords passing has too much of a vertical component of velocity and not enough horizontal component. The ball is lofted and resulting in interceptions instead of scoring. Bradford needs to decrease that angle to score. Hopefully the Vikings read this post and start winning again!

Licking a Battery

Recently in our APC physics class we have been doing electricity and magnetism and therefore our labs include creating circuits with wires, resistors, breadboards and batteries. I believe one of the most important things I learned from this lab was that licking a 9-volt battery gives you a shock. I thank Mr. Fullerton for teaching me this trick. When you lick a 9v battery, your tongue acts as a conductor as it is wet and therefore electrons are free to move, both ends are touching your tongue and therefore a mini circuit is created. If you feel a slight shock, that's good: your battery is all charged up!

Lebron James Flopper?

On Monday, the defending NBA champions, Cleveland Cavaliers, played the runner up Golden State Warriors for the second time this season. The Cavs were looking for their 5th straight win in a head to head match up against the Warriors, however, the Warriors (with all 4 1/2 of their All-stars) handily defeated the Cavilers in this match up. The controversial play of the game was a Flagrant foul by Draymond Green on Lebron. The question is, did Lebron Flop? We can answer this question using physics and momentum.  As we know, when two objects collide, whether an elastic or inelastic collision, momentum is always conserved. Therefore, if we calculate the momentum of the players before and after the collision, we can decide if Lebron flopped  or if it was all from Draymond. According to an article from Wired.com author Rhett Allain calculates the momentum of the players. Based on the players listed masses and video analysis he found that this was the data: "LeBron before the collision = +548 kg*m/s LeBron after the collision = -264 kg*m/s Draymond before the collision = -362 kg*m/s Draymond after the collision = -290 kg*m/s" (Allain, Wired.com).  Now if we use this data, the momentum before the collision was 186 kg*m/s in the positive direction, while after the total momentum of the system was 554 kg*m/s in the negative direction. Clearly this is not conservation of momentum so an external force was provided. This force was provided by Draymond legs pushing on the ground. So, yes, Lebron may have flung his arms, but Draymond certaintly did provided an extra force to push Lebron down.

Final Video Project

Hey Mr. Fullerton and anyone whos reading this, its been a pleasure grinding this year. Hope you enjoy this great video and maybe even chuckle a bit.

Failure IS an Option

On Friday the 16th in AP Physics C class, Mr. Fullerton assigned us a lab with a very simple task: shoot a ball to hit a book, if it hits the book the whole class passes, if it misses the whole class fails. Although the task seems simple, there were multiple layers to this problem, clearly with high stakes. Through this lab we were to use our skills of kinematics to determine the velocity that the instrument shoots the ball at, and then use this information to place the book at the correct location. Furthermore, we were asked to work as a class really testing out communications skills. The 22 kids in this class are some of the brightest in the school, yet our communication is where we failed.  While we should of broken up works into different groups, the whole class was all over he place sound different things, and using different values. Personally for me, my problem was trying to find the exact time of the first trial, and this prevented me from having a sufficient amount of time to do the math. Also, a problem we had when calculating the distance was using the displacement direction as a negative and the acceleration as a positive. Because the vertical displacement of he ball and the acceleration due to gravity are in the same direction, there signs should be the same. This was a vector analysis that further screwed up our final values. After making this change in the math, I was able to find the true velocity of the ball (using the equation d=(1/2)at^2+vt). With this information I could then find the distance the ball should travel with instrument set to a new angle of -4°. Using a two step kinematics problem (work attached), I was able to find the new displacement to be 1.92m in the x-direction. This value is very accurate to the actual loctation of the second firing, and if we had fixed these probaes we would not have failed.  The simple truth of it is that we did fail, as at the end of the period we were pressed with time and placed the book at a pretty random  eye-balled location. It's ok for us to fail because if we analyze our failure we can learn and then chances our, we will do it right the next time!

Driving on the Highway

Whether you notice it or not, there are fundamental concepts of physics on your way to the grocery store. For one thing, in an average car ride all three types of acceleration happen: acceleration, deceleration, and turning. Another thing, riding fast in a car helps me to understand concepts of inertia. When I was little, we would be traveling 50 mph down the highway, and I would throw a tennis ball in the air. The tennis ball moved with the car. I asked my dad why the ball didn't go flying to the back of the car. That was the moment I learned about the concept of inertia. Lastly, on highway 104, there is a very large round about turn. Every time we make this right turn, I feel as though I will fly to the left side of this car. Knowing physics, I now know that inertia is what makes my body feel that way, and the centripetal force of friction keeps me from doing so. I could even calculate the force felt by f=mv^2/r.

CSI: Who Done it?

Today in physics class we did a little something special; a fun activity investigating several crimes. Whether these crimes were really in the local area, or a figment of imagination, it was still interesting to pick them apart to find out the culprit. The first crime scene was a murder, murder by gun. We had to decide which gun did the killing and based on small pieces of evidence, and by knowing this gun we could match it up with certain people. We knew the initial height of the bullet (the exit wound) to be the height of the victims shoulder, and the final height the height of the hole in the wall. Using this displacement, the acceleration due to gravity, and the fact that the bullet traveled horizontally, the time could be found. Finally, using this time and horizontal displacement, we discover a velocity 30% as strong as the velocity fired, and the pieces match up. Secondly, a body was found dead at the bottom of a hotel after Alonzo Green supposedly tried to jump to the swimming pool. We have to decide if he jumped, or was pushed. Once again, using kinematics we can find the time it takes for a person to fall the given height. The given height could be measured with a diagram and a conversion scale from cm to meters. Once we have this time, we are given  the max velocity of a 45 year old male sprinting to be 6.9 m/s, and this velocity will leave a person 2 meters short of the pool, exactly what Alonzo was. He jumped. Lastly, Evelyn Horton drove her car off a bridge when she supposedly was sabotaged by a raging driver. However, she may be just saying this to avoid embarrassment, and so we want to know which is true before moving in to a long term investigation. Once again, kinematics are used to find the time it takes the car to fall a certain distance, and therefore allow us to find the initial velocity when hitting and breaking the rail. Horton claimed that she decelerated at least 8.83 m/s/s before hitting the rail, however, with her given initial velocity, her final velocity with this acceleration would be to slow to make it as far as she did, therefore she snoozed.  All in all, this was a fun activity that put a spin on our daily routine in APC, and the extra credit definitely made it competitive and fun

Better to Run or Walk in the Rain?

A very popular and interesting YouTube channel I watch is minute physics, where a guy does short videos on different concepts of physics. One video I have recently watched is about whether it is better to run in the rain or to walk in the rain. In other words, which choice will get you least wet. For one thing, the amount of rain that falls on your head is constant, as when you move out of the way of one rain drop, you move into the way of another rain drop. However, if you are the more horizontal distance that you travel, the more rain will hit you from the side. Therefore, the faster you move, the wetter you become. However, when you are trying to get from one point to the next, the amount of rain you run into will be constant (like a snowplow plowing a volume of snow, the speed it plows it does not change the amount). Therefore the answer is simple: Run. The less time spent in the rain, the better.  Credit to minutephysics (at YouTube.com)

Better to Run or stay out in the cold?

I watched a video from the YouTube account MinutePhysics and it was very interesting about conservation of energy, and staying warm in a cold climate. This video was similar to the one I wrote about in an earlier blog about it it's better to run or walk in the rain.  Anyway, the video basically explained that when a person is in a very cold situation, the surface area of they're body exerts almost a protective layer of heat around they're body, of course they will still feel cold in freezing temperatures, however they are warming than they should be. When runnning, there is a draft force and therefore air resistance on ones body, and not only does this cool air make a person cold, a person is running away from the layer of heat their body creates. It would seem obvious to stay put then to stay the warmest right? Not exactly. When humans run, approximately 80% of their energy exerted is converted into heat energy. This heat energy warms a body up, but is it enough to outway the new cold faced by the person, because he faster one runs, the greater he air resistance. Well it turns out in freezing weather a person would have to run about a 6 minute mile to stay warmer than staying put. Moral of he story, wear a parca!  Here is the link to he video I saw this on

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