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ncharles

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  1. ncharles

    Stage Curtains

    By ncharles,

    If you have ever went to see a concert, play, musical or any other performance on a stage, it is very likely that there were curtains involved. Tonight, i was partly responsible for the curtains at the IHS Talent show. The contraption that allows the curtains to move across the stage is a simple pulley system using two pulleys and a rope in-between. When the rope is pulled in one direction, it creates a torque on the pulley and causes it to spin. This spinning either opens or closes the curtain (depending the direction pulled). This contraption is also very common with close-able curtains in your home. And this is a very simple example but i realized thats some of the most simple things help the most!
  2. ncharles
    Billiards (aka pool) is a common sport in which the competitors try to knock their balls (either stripes or solids) into cups around the outside of the table. They use a Pool Cue to hit the Cue ball into other balls which will cause them to move in certain directions and ultimately into the cup. This sport is different than others because it SCREAMS physics: collisions, angels of incidence and reflection, friction and many other concepts are what this sport revolves around. First off, when the cue ball collides with other balls (assuming perfectly elastic collisions) momentum is conserved. This comes into play when the competitor is judging the amount of speed necessary to complete a shot. The more speed the cue ball has at impact will mean that the speed of the ball it hits will also increase. Another shot to perfect in billiards with the bounce shot. More often than not, the balls are not perfectly lined up to get the best shot possible.....so, the competitor needs to utilize the walls and bounce the ball off the wall in order to hit the target ball. When judging the angle to bounce the ball at, the competition must know that what ever angle the ball hits the wall with is the same angle it will bounce off with (angle of incidence=angle of reflection). Finally, frictions plays a very important role in the collision of the cue stick and the cue ball. Professional pool players put spin on the cue ball in order to make it do different things to give them an advantage. Often, the player will put chalk of the end of the pool cue to increase the friction between the sick and the ball which will increase the amount of spin on the ball and with more spin comes better results. So next time you play pool, think of the physics behind it.

  3. ncharles

    Water Skiing

    By ncharles,

    Similar to tubing, another aquatic sport that i love to participate in is waterskiing. Something about gliding across the water gives me a sense of freedom that nothing else really does. Water skiing is a great example of physics too. Firstly are the turns. When a water skier decides to turn, they must angle their skis in such a way that makes them go where they want. Two main factors effect the turn: the angle and the force. The more of and angle the skier tilts the skis at the bigger and sharper the turn will be. However, skiers usually take long circular turns which require a much smaller angle. The "force" exerted by the person into the turn makes the turn faster or slower.  When the skier finishes their turn, they will next jump across the wake...a perfect example of projectile motion. The skier comes to the wake with a starting velocity that they must perfect: if too fast, they will over shoot the other side of the wake and if too slow they wont make it at all. Also, the make form a "ramp" of water at an angle to the surface of the water which the skier must also analyze to see how fast to go.
  4. ncharles

    Zip-Lines

    By ncharles,

    Something i have always wanted to do is go on a zip-line in a forest or down a hill. However, what i did not think about are the many applications of physics in zip lining. The most obvious the use of gravity to propel you down the line. Gravity will act down on you at the center of you mass and accelerate you in a wild ride of fun. The zip-line actually works by putting a contraption on the line that has multiple wheels in it. The line is notched in the wheels and a low amount of friction allows the wheels to spin very fast while traveling down the wire (pulled by the force of gravity). At he end of the zip-line the most common way to stop is using a spring. The spring will be coiled around the wire so that when you hit it, it cushions your impact. The more you compress the spring the harder it will push back on you which insures that you will not hit the wall/tree/post it is attached to.
  5. ncharles

    Pressure in Bottle

    By ncharles,

    I saw this video recently and thought it was a very cool experiment and not a normal application of physics. When the hot air in the bootle begins to cool down, it create a vacuum in the bottle and applies a force on the water up through the straw. This force gradually goes to zero and the pressure inside and outside the bottle begin to equal each other. Maybe you should try this at home! 
     
  6. ncharles

    Tubing

    By ncharles,

    As this year comes to a close, the activities of summer are finding their way into my head more and more each day. One of my favorite things to do is go tubing. Besides an exciting water ride, tubing is a great example of physics is the real world. The boat pulling the tuber is an example of Newton's Third law: for ever action there is an equal and opposite reaction. The propellers on the boat push on the water which pushes back on the boat to propel it forward. The rope that connects the tuber to the boat must be a very strong rope due to the high amounts of tension it must withstand. Finally comes the tuber. There are two main friction points that make tubing great: between the water and the tube and between the tube and the person. The small amount of friction between the tube and the water allow the tube to go fast glide on the water. The friction between the person and the tube allow the person to stay on but it isn't large enough to make it easy for the person to stay on. 
  7. ncharles

    Golf

    By ncharles,

    In my eyes, the sport that uses the principles of physics most simply is Golf. Kinematics and projectile motion are the biggest components of physics that are applied in golf due to the objective of hitting a ball into a small hole. First, the angle at which each club is tilted determines the total distance the ball will fly. A club with a very low angle of tilt, such as a driver, will cause the ball to fly the farthest. But the angle isn't the only factor to distance. Comparing a driver to an iron, the weight and size of the driver's head is greater in both cases. This means that the driver will hit the ball with more force (assumed the swing speed is the same). Another application of physics in golf is air resistance. If you have ever held a golf ball before, you would have surly noticed the dimples. These dimples actually decrease the effect that air resistance has on the ball and allow it to fly faster and further. This happens because the dimples decrease the surface area that the wind hits and causes smaller drag force on the ball.
  8. ncharles

    Relative Speed

    By ncharles,

    Another idea that came up while flying to Florida was the principle of relative motion. When ever people are traveling they are usually only focused on their speed and not that of others. However, as i looked out of the window, I saw another plane in the open sky and it seemed that it was going much faster than us. However, knowing the principle of relative motion, i realized that we were most likely flying at similar speeds and it only seemed that the other place was flying fast because we were flying in different directions. Due to this, the relative speed of the other plane from my perspective would be our speed plus the speed of the other plane. However, if we happened to be flying in the same direction. the relative speed of the other plane would be the absolute value of my speed subtracted from their speed. So next time you travel know that things in your surroundings are not moving as fast as they seem to be.
  9. ncharles

    Planes

    By ncharles,

    A common way to spark ideas for this blog is to do cool stuff and have amazing experiences. And although flying in a plane is not such an “amazing” experience, it has sparked a couple ideas that I would like to share. As I was flying, I began to think “How exactly does a plane fly?”.  Newton’s Second Law popped in my mind thinking that we are obviously not accelerating in the y-plane so the force of the plane up must be equal to the weight of the plane (mass times the force of gravity) Although the weight of the plane would vary with our altitude, the change is rather negligible to the scale of forces we are talking about. And since we are in-fact moving in the x-plane the must be a force directed in the -x-plane to cause moving in the +x-plane. So I came to the conclusion that the engines in the plane must produce two forces, one up to counteract gravity and one back to actually cause the plane to move. I know this is a rather simple observation but it was something I had never thought of until now!
  10. ncharles

    Toy tops

    By ncharles,

    The spinning top, a toy found across many of the world's cultures is a great example of a few key physics principles. The first is the conservation of angular momentum: with no outside forces present, something spinning must keep spinning. Because a top balances upon a tiny point, the is a nearly negligible amount of friction, and it continues spinning for a long time, demonstrating the law. But as friction slows the top, it becomes unstable and starts to wobble, leading to another principle called "precession." When the top wobbles, its axis of rotation tips sideways, making an angle with the table. This angle allows the force of gravity to exert a "torque" on the top, putting additional spin on it, and this causes it to swing (or precess) outward in an arc, still spinning as it does so. In an effort to conserve its total angular momentum, the top precesses faster the slower it spins; this explains why tops typically lurch outward just as friction brings their spinning to a stop.
  11. ncharles

    Kayaking: The Basics

    By ncharles,

    Almost everybody knows what kayaking and a majority of the population probably have kayaked before. However, like many other things in the world, people may have not thought of the physics of kayaking which is a perfect example of Newtons Third Law. While paddling, you are applying a force on the water by torque on the paddle. If you have ever experimented with paddling, if you hold further towards the end of the paddle, if is easier to go faster. However, if you choke up the the paddle alot you wont be ablle to go as fast because, due to the length of the "lever arm" being decreased, the torque applied to the water is much less. When you apply the force onto the water, by Newton's Third Law, the water applies an equal an opposite force on you (and the kayak) pushing you forward and allowing you to move.
  12. ncharles
    As an avid saxophonist myself, i have never really thought about how and why a saxophone worked as it does. However, after great thought and research, i have found that the sound produced is due to three main parts of the saxophone: the mouthpiece, the holes along the body of the saxophone and the bell. The most important part of creating a great sound is the mouthpiece. When the musician blows air into the mouthpiece, it causes the reed to oscillate between the mouthpiece being open and closed. This oscillation of the reed creates sound waves when i vibrates. The note created is based on the amount of holed closed by the musician, when more holes are closed it lengthens the sound wave and created a lower tone. When playing a alto saxophone with all the holes closed, it plays a Bb3 which has a wavelength of 25 inches (.635m) and speed of 344.5 m/s. By using the equation v=fλ we can find that the frequency of this note is 271 Hz. Finally, the part of the instrument that amplifies the sound is the bell. The bell disperses the sound waves into all directions to fill the room the saxophone is being played in. This gives it a bright sound and overall improves the music played.
  13. ncharles
    Everyone inter life has shocked someone by rubbing their feet on the ground and then touching the other person. It is a classic trick often pulled in the winter. However many people don't know why or how this happens. Well the first step is rubbing your shocks, preferably wool, on the carpet. This causes your socks to "steal" electrons from the carpet and make your socks negatively charged. This is obviously not the state that the electrons want to be in so at any chance they can get they will jump over to another, more positively charged, object. So when you go to touch your friend, they are usually neutrally charged so to create and equilibrium, the electrons jump over to your friend causing it to shock them. This prank works better in the winter because with the winter come less humidity and less water vapor in the air. And we all know that electricity and water are never a good mix so the less humanity makes it easier for the electrons to travel from objet to object. 
  14. ncharles

    Winter Driving

    By ncharles,

    As all Rochesterians know, winter driving is not easy and can get out of hand very easily. But why? Well it is rather simple. The added snow and ice on the road causes the coefficient of friction between the tires and the road to be much much smaller. Using the equation Ff=uFn with Ff being the force of friction, u being the coefficient of friction and Fn being the normal force we can see that when the coefficient of friction decrease (while the normal force is kept constant) the force due to firkin decreases. This causes the tires to slip a lot easier on the snow and ice than it would in just dry pavement. Similar to driving on snow/ice is driving on water. Although not a sever, when the road is wet the coefficient of friction between the tires and the parent is less than dry parent but not as less as snowy or icy pavement. So when you go driving this week be extra careful and be ready for a spin out.
  15. ncharles
    As i watch the Denver Broncos play the New England Patriots in the semi-finals of the road to the Super Bowl, I have realized at how important the position of the quarterback is. Inorder to be successful, the quarterback must have keen senses and know the basics of physics. When looking deep to an open receiver, the quarterback is able to subconsciously analye three main components to the throw...the angle, speed and timing (a classic example of projectile motion). The quarterback must know exactly what angle to throw the ball at in order to loft it perfectly into the path of the wide receiver. A fluctuation of a mere 5 degrees could be the difference between a touchdown and a turnover. Second is the speed. The quarterback must be able to throw the ball with enough speed to get it to the hand of the receiver without throwing it too far and over throwing the receiver. Also, if they speed it to small, the defense will easily intercept the ball and possibly score. Finally, arguably the most important aspect of throwing a deep ball is timing. If the quarterback throws the ball a second or two too early or too late, it will miss the target receiver and result in an incomplete pass. 
  16. ncharles

    Snowshoes

    By ncharles,

    Have you ever had to walk through feel of snow and your feet just fall right through it? Well this has happened to me more times than i can count. Although i do not own a pair, the great invention of snow shoes were intact created to solve this simple problem. The problem without snow shoes is that your weight is distributed on such a small  area that the snow cannot hold you up and you can easily comports the snow. The purpose of snow shoes is to increase the area that your weight is being distributed on. This increase is weight distributions cases less force to be applied on each snowflake which would make it compress much less. 
  17. ncharles

    Bombs Away!!

    By ncharles,

    In the history of the world, there have been millions of bombs dropped by any nation during a war. However, what most people never think about is the physics behind dropping a bomb. The bombardier must take into consideration the speed at which they are flying, the horizontal distance away from their target and the height at which they are flying. Say, for example, the average B-42 bomber has a cruise altitude of 39,00 ft (12,000 m) and a cruise speed of 545 mph (926 kph). If a bomb were to be dropped with these conditions, the bomb would travel a horizontal distance of 12.72 km in its fretful in 49.5 seconds (ignoring air resistance). If the bomb team was given a target to hit with a radius of 1 km, then mistiming the drop my a mere 5 seconds could cause the bomb to miss by 300 m. This could mean the difference between winning or losing an entire war...some pretty big stakes. Luckily now there are bombing systems that are very accurate and a bomb team is no longer required; but back in the day, this was a stressful task that took much focus and careful calculations. 
  18. ncharles

    The Physics of "Sweat"

    By ncharles,

    Many people may be familiar with FIFA (Fédération Internationale de Football) and possibly the FIFA video game put out by EA Sports also. To the average person, the video game FIFA may seem dumb or boring, however, as an avid FIFA player myself, i experience a very exciting roller coaster of emotions when i play. There are many techniques to play FIFA that will all lead to success; but the technique that is the most effective and efficient is called "Sweat". The goal (pun completely intended) of this technique is to cross the ball from the sideline and head it in to score a goal, however it is more complex than that. First off, the user must find a suitable player to run down the sideline with. The only attribute that this player must possess is pace. There are two components pf pace: acceleration and speed. The acceleration, as we all know, is the rate at which an object gains speed. If the player of choice has a greater acceleration than the opponents player, your player will be able to cover the same amount of ground in a shorter time which will allow your player to create a gap between him and the opponent. Speed is also very important in order to maintain the gap created and not be easily caught by the opponent; these two attributes combined prepare for the second step: the cross. There is a lot that goes into the perfect cross. First the player must rotate their hips with a very high angular speed in order to send the ball in the correct direction. Second, the player must kick the ball with the right force and at the right angle to place it just in-front of the player that is aiming to head the ball to score a goal. Finally, arguably the most important step to the process of "Sweat" is the header. The model header is 6'3" or greater in hight and VERY strong. This makes it easy for them to head the ball because they do not need to jump as high to reach the ball at the maximum height possible. Also, the player heading the ball must mentally time the header in order to redirect the ball a full 90 degrees to get it on target. This requires a very fast turn of the head, similar the the rotation of the hips on the cross, with a very high angular speed. After the header happens, the goalie will have no time to react and the the ball will go in the goal without a doubt.
  19. ncharles

    Shaking trees

    By ncharles,

    Have you ever looked out of the window on a windy day and noticed that only the tops of the trees are shaking? The answer is most likely yes but you probably haven't thought of why this happens. The wind in general applies a force on the tree witch is what causes the tree to move, however, the tree can withstand some force and keep sturdy. As the force of the wind is applied further and further up the tree, the torque in being increased because the length of the "lever arm" is being increased. The maximum torque at the very top of the tree passes the threshold force that the tree can withstand and causes motion at the top of the tree! 
  20. ncharles

    Schlieren Imaging

    By ncharles,

    Schlieren Imaging is an optical technique which allows viewers to see physical changes in air which the human eye cannot detect. Like many other imaging techniques, Schlieren Imaging involves a few basic principles such as refraction (how light acts/bends as it changes medium), reflection (the act of light bouncing off of a reflective object such as a mirror), refractive index (the amount light bends as it passes into a certain material) and density (which affects refractive index). A Schlieren Imaging System allows one to see the different densities that light rays from a source pass through: even if not visible to the human eye. One of the most common ways of setting up a Schlieren Imaging System is the “z-style” (as shown in the attached diagram). This includes a single concave mirror, a light source, a knife edge or color filter, and a camera. As shown in the diagram, the light shines onto the mirror, which reflects and focuses the light to a single point onto the knife edge. The knife edge is used to block out light bent at a specific angle due to a density change in its path. This blocking of light creates a dark spot in the image or field of view which gives the image contrast and clarity, alowing you to be able to see the pocket of air of different density.

  21. ncharles

    The Perfect Free-Throw

    By ncharles,

    Sports have been a large topic of focus in this here blog and i will continue that trend with a new application of physics...BASKETBALL.  Now many people may think that basketball is a simple game of putting a ball in a hoop but it is much more complicated. Im only going to focus on the free throw in this post. The first part of the free throw is lining up your shot. This takes practice in order to learn the typical trajectory of your shot so that you now what angle to shoot it with, the amount of force to apply to it and the night to shoot it from. Right after the shot comes the follow through. The main part of the follow through is to apply backspin to the ball. This makes the shot more likely to go in because rather than bouncing normally, the backspin decreases the angle of "reflection" (for lack of a better term) of the ball and keeps it closer to the hoop so it can roll in. 
  22. ncharles

    Popping Ears

    By ncharles,

    Have you ever experienced your ears popping before? Why does this happen? Well, you ear has a small pocket of air in it that, usually, has the same pressure as the outside air.  However, when you are on the takeoff or decent of a plane ride the atmospheric pressure of the air around you is constantly changing at a fairly fast rate. Inside your ear there is a small tube which is made for equalizing the pressure of the air in your ear and the air outside your ear. This opens when you swallow and often when it is opened you hear a pop; and that is the pop you hear. The bigger the difference in pressure the bigger the pop. So next time this happens to you, don't be scared...its completely normal!
  23. ncharles

    Curling

    By ncharles,

    As you may have figured out already, I tend to enjoy writing these blogs about sports and fairly dangerous activities...so I will continue this trend with curling. Although not the most exciting sport to watch, playing it is a whole different story due to two main physics principals: friction and collisions. Curling is played on a ice surface to allow the stone to glide easily and smoothly to the target because the friction between the ice and the stone is very little. If you've ever seen even one throw of  a curling game then you have seen the people so stand there with brooms and brush the ice and you probably thought "well that just looks silly" (myself included). Well there actually is a purpose to this; the act of brushing the ice causes the top layer of the ice to met and turn in to water. The friction between the stone and water is much greater than the friction between the stone and ice. So, what these people are doing is slowing down the stone in order to make it stop right in the middle of the target circle.
    Similar to billiards, curling is filled with collisions; and that is the biggest part of the game. The ability for the thrower and the 'brushers" to judge the speed and direction necessary to accomplish a task is key to the sport. For example, is the thrower throws the stone way to fast, the brusher wont be able to stop it and then is will smack into every other stone and they will all be scattered in every which way. This obviously isn't what is wanted because the task of stopping in the middle was not achieved. Rather, the thrower wants to throw it at just the right speed in order for the stone to collide with one or more stones and stop right in the middle while sending the other stone out of the target area. So, next time you watch or play curling, you will actually know what the goofy people with the brushes are for!
  24. ncharles
    On thing that i would love to do in my life time is go skydiving. Fro what i understand there are three main parts to a skydive: free-fall, decent by parachute and touchdown. During free-fall, you re acceleration toward the earth at a rate of 9.81 meters per second per second.  This just means that every second, you increase your velocity by 9.81 meters per second. However, due to air resistance, there is a maximum velocity that you reach because once you reach that velocity the drag force is equal to the force of gravity with causes a balance of force and therefor no acceleration. Second is the decent by parachute. When you first open your parachute, you slow way down because air resistance is greatly increased due to the parachute...which is its job. When the parachute is out, the rage force is equal to the force of gravity with allows you to fall at a constant speed. Then finally, touchdown. When landing back put earth, it would be smart to tuck and roll rather than just land. The reason for this is that if you do this you act sort of like a spring and don't take all the force at once but take it little by little. This will prevent injury and make your skydiving experience a lot more fun.
  25. ncharles
    A common activity that nearly any person ever could participate in is bowling. Whether you're a 35 year old professional, scoring 300 like its nothing or a 5 year old beginner using the bumpers, there still is one thing that always stays the same...physics. First of all, if you've ever stepped over the line while bowling, chances are you slipped and fell...why? The lane of the alley must have nearly no friction in order for the ball to maintain its initial speed, and to allow for better control of the ball and the application of spin. That brings us into spin. When a player apply spin to a ball the rotational inertia causes the direction of the ball to be altered based on the direction and amount of spin. Professionals look to make the ball travel in a near parabolic path in order to maximize the chance of getting a strike. 

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