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jwdiehl88

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  1. jwdiehl88

    Airplanes

    By jwdiehl88,

    The last time I was on a airplane was when I was traveling to Florida for vacation.  I wondered how almost 200 people and the mass of the plane didn't weigh the plane down.  The forces on the airplane is at equilibrium when the airplane reaches at a certain altitude.  Additional when the airplane reaches at a constant velocity therefore the forces on it all must be balanced.  This means that the lift force (L) generated by the airplane wings must equal the airplane weight (W), and the thrust force (T) generated by the airplane engines must equal the drag force (D) caused by air resistance.  The airplanes wings and the fins in the back of the air plane, cuts down on drag force and increases the lift of force when the plane is increases its altitude.  The wings and fins makes the airplane aerodynamic letting the airplane go faster when its flying in the air.  
     
     
     

     
  2. jwdiehl88

    Breaking a Board

    By jwdiehl88,

    I used to practice martial arts and one day in our dojo, my sensei decided that we should have fun by breaking boards.  Although breaking a board seems impossible for a person who doesn't do martial arts, it is quite simple if we look at the physics of breaking a board.  For example, a person needs to generate a certain velocity to impact the board at a certain position.  A person should make the impact/position of where your hands end, up past the board.  Otherwise your hand will have a tendency to slow down when it reaches the actual position of the board.  Additionally, a person should position their strike on the board where the board it weakest.  For example if you punch the center of the board, it is harder to break it because that's where it is the strongest.  On the other hand, if you punch a board at the near an end of the board, it will break more easily.  It can still be very hard to break some boards because of how the thickness of the board.  As the board increases in thickness, you velocity of the strike has to be fast and more precise on the board. 
     
  3. jwdiehl88

    Cello

    By jwdiehl88,

    Cello, the best string instrument, creates beautiful music.  But how does a cello create sound?  Well, sound is produced by the vibrations of the string, and these sounds resonate inside the cello.  Cello strings are fifths (five notes apart) and each string creates their own frequency when you place your finger down on different parts of the string.  As you place your finger down the fingerboard to the bridge of the cello, it creates a higher frequency.  As you place your fingers up the fingerboard, it creates a lower frequency.  Each string has different frequencies because of the thickness/wavelength of the string.  The more thick/smaller wavelength the string is, the lower frequency the cello creates.  Additionally, cello's have harmonics on each of the four strings.  Each at a difference frequency and when you play the harmonic, it produces a loud clear sound.  When you play a harmonic, this creates a shorter wavelength which in turn produces a higher frequency sound.  
  4. jwdiehl88

    Curving a Soccer Ball

    By jwdiehl88,

    Curving a soccer ball, seems easy enough.  Everyone is able to do it, on purpose or accidentally.  All you have to do is kick a soccer ball.  And yet, there is so much physics in how a person can curve a soccer ball.  The reason a soccer ball curves is because the kicker kicks the ball at a certain angle and velocity causing the ball to spin.  However, once the ball is in the air, it is really the air that is curving the ball.  This seems impossible, but the air resistant will curve and bend the ball in a way.  The Magnus effect is a lift force that causes the ball to curve through the air.   As a spinning ball moves through the air, it spins a boundary layer of air that clings to its surface as it travels along. On one side of the ball the boundary layer of air collides with air passing by. The collision causes the air to decelerate, creating a high-pressure area. On the opposing side, the boundary layer is moving in the same direction as the air passing by, so there is no collision and the air collectively moves faster. This sets up a low-pressure area. The pressure differential, high on one side and low on the other, creates a lift force (the Magnus force) that causes the ball to move in the direction of the pressure differential.  The force can applied to any direction, for example, backspin, topspin, and side spin.  Down below, I hope you enjoy the craziest curve shots! 
     
     
     
     
  5. jwdiehl88

    Dancing

    By jwdiehl88,

    Both of my sisters used to dance and when I was younger I went to their dance recitals.  Every year I went, there was always that one dancer who would spin on her toe for the longest time.  I always notice that when ever the dancer slowed down while spinning, she whipped her legs around in a circle again and then she started to spin faster.  I have always wondered how one leg motion could keep you spinning for the longest time.  Well this simple spinning of a dance can be explained through angular momentum.  When the dancer starts she extends her legs out to have a larger radius.  With this larger radius, her angular speed is small, but when she whips her legs around and tightened up her leg to her body, the radius is smaller.  The angular momentum is the angular speed times moment of inertia initial equals the final.  The dancer with the large radius has a large moment of inertia and low angular speed.  When she brings her legs together, the moment inertia becomes less and the angular speed increases.  Therefore she can spin faster when she puts her legs out and then whips it back into her body. 
  6. jwdiehl88

    Explosions

    By jwdiehl88,

    It's hard to think about a how an explosion has momentum conserved because an explosions blows up everything in little pieces.  However, those infinite amount of pieces all contribute to conserve the momentum of the explosion before it exploded.  The law of conservation has a simple equation of mass times velocity initially equals the mass times velocity final.  An explosion before it happens is equal to zero because it has no velocity at all.  After the explosions, the pieces broken off in the explosion will go everywhere.  The direction of the pieces matter because after the explosions, the direction of the pieces will have equal magnitude but just in the opposite direction.  So when you had up all of the individual pieces of its direction, mass and velocity, the pieces will even each other out.  Therefore the sum of all of the infinite pieces after the explosion will have a momentum equaling zero.  Therefore the momentum of the explosions is conserved.  It's crazy to think that the aftermath of an explosion has zero momentum.
  7. jwdiehl88

    Eyes

    By jwdiehl88,

    I have horrible eye sight, so that's why I need glasses to see better.  And yet I never really understood how a mirror could make you see better.  Until last year, when we learned in physics of optical glasses.  Our eyes are concave, and the distance between our cornea to our retina is the focal length.  So the light that hits our eyes allows us to see images.  People who have twenty/twenty visions have eyes that aren't small or elongated and the focus is at the retina.  This allows people to see images clearly.  However people who have bad eye sight can either be far-sided or near-sided.  The people who are far-sided, have their focus behind the retina because the eyes are short, therefore convex lenses can fix this.  Convex lenses has a positive focal length which moves the image of a person far-sided forward.  People who are near-sided, have their focus in front of the retina because the eye is elongated. Concave lenses can fix that because tit has negative focal length so it moves the image back to focus.
  8. jwdiehl88

    Ferris Wheel

    By jwdiehl88,

    A couple of summers ago, my family and I went to Hersey Park for vacation.  I'm afraid of heights but I love to go on roller coasters and I remember that there was a Ferris wheel that my sisters persuaded me to go on.  It was scary because you could see how high you were from the ground.  But it was also cool because you could see everything.  Anyways, a Ferris wheel can be related to physics because of its shape.  It is related to centripetal force and torque.  So basically, I could calculate the torque that a rider feels on the Ferris Wheel.  All I need is the radius, the mass, and the linear acceleration.  To find the linear acceleration, I would calculate the centripetal acceleration of the Ferris wheel.  So I would need the velocity and radius of the rider.  Then I could convert the centripetal acceleration to angular acceleration.  Then I would calculate the moment of inertia by doing mass times the radius squared.  Finally to find the torque I would do the moment of inertia times the angular acceleration. 

  9. jwdiehl88

    Firing a Gun

    By jwdiehl88,

    Recently I was watching Point of Interest, a TV show, and I was thinking about what kind of physics are behind firing a gun.  I concluded that when the shooter shoots a gun, the force on the bullet is equal to that on the gun-shooter. This is due to Newton's third law of motion (for every action, there is an equal and opposite reaction).  The force of the bullet is equal to the gun-shooter due to the law of conservation of momentum.  A person with a gun have a combined mass M and the bullet has a mass m. When the gun is fired, the two systems move away from one another with new velocities V and v respectively.  Also, the person with a gun moves in the opposite direction of the bullet.  Therefore, the initial momentum is equal to the final momentum due to the law of conservation of momentum.  Since the net force is equal to the change of momentum, the initial change of momentum of the person and gun is equal to the final bullet's momentum.  Therefore, the person with a gun has a equal force and a opposite direction of the bullet.  
  10. jwdiehl88

    High Jumping

    By jwdiehl88,

    Watching the summer Olympics last year was really intriguing because of the High Jump.  I have always wonder how someone with just a pole could jump so high above a bar.  Now I know there's physics behind it.  First of all, before the person jumps above the bar, the person with pole has  to generate speed to the high bar.  This speed generate before the person jump increases the kinetic energy of the person.  Then the person plants the pole down at an angle and jumps, the person is then able to be at the highest trajectory of their motion.  Additionally, the kinetic energy of the person is then transferred into potential energy causing the person's height to increase.  This allows the person to jump at a high height and be able to be at the highest point of its trajectory.  The hang time of the person in the high is due to the pole's elasticity.  The pole bends then whips the person to the bar, causing the person to have a longer time in the air.  Then the person has to arc their backs to get over the high bar.  Then they land on the soft pads to help their landing because it increases the time of the force impacting the body causing no harm to the body. 
  11. jwdiehl88

    Hockey Shots

    By jwdiehl88,

    Shooting a puck, wrist or slap shot, requires a player, using their stick to apply a force greater than the frictional forces(very little, due to ice being relatively smooth) resisting the puck's movement.  Players have the ability to generate lift because all stick blades have a certain "tilt" angle.(the face of the blade is turned slightly upwards).  During the shot, the puck slides along the face of the blade and it is the tilt which allows it to be lifted off the ice surface.  Players who generate high speed velocity of their slap shot, has a large force and time of impact of the blade and hockey puck.  Players wind up for a slap shot, to generate a large force and then hit the hockey puck in a certain time.  Force * time = impulse = change of mass * velocity.  Therefore a large impulse equals a pretty large velocity.  Players who attempt wrist shots, have a less wind up because they want more accuracy then power.  The less force the player has on the hockey puck from the blade of the stick, means less impulse.  Therefore a lower velocity of the hockey puck relative to the hockey puck hit by a slap shot. 
  12. jwdiehl88

    Hovercraft

    By jwdiehl88,

    The hovercraft hovers by creating a cushion of air with enough pressure to the weight of the craft and the passenger.  The fan constantly blows air molecules into the cushion.  The cushion inflates, and there are a couple of holes in the cushion that allows some air molecules to escape so the cushion doesn't explode from the pressure.  The trick to get the craft to hover is to have the air molecules exert greater pressure or force than the weight of the craft.  The air pressure needed to lift the hovercraft equals the weight of the craft and the passengers divided by the area. Pressure = Force / Area.  It seems like pressure and area are inversely proportional, however, the larger the surface area, the greater the weight of the craft and therefore more pressure would be needed.  Also the larger the area, the greater drag or resistance on the craft is created.
  13. jwdiehl88

    Jenga

    By jwdiehl88,

    Jenga, it's the classic block-stacking, stack-crashing game that everyone played as a kid. You and the person you played with, stacked up pieces of block into a sturdy structure and then you remove these blocks from the bottom or middle and placed them on the top. As you removed a block from the structure you had to be careful of how you removed it because one wrong twist or turn, you could collapse the structure and lose. The reason why it's so hard to remove the block from the structure because there is a friction on the block that resists you from pulling the block fast and smoothly. If the block isn't removed smoothly then the structure will collapse. The reason why this game works and why the structure stays in place when you remove blocks is because of the center of mass of the structure.  Even if you take a block from the middle of the structure, this doesn't affect the structure to fall down immediately because the center of mass doesn't move when move the block. It stays constant and keeps the structure from falling. Since the center of mass of the structure doesn't move, the only time it falls is when a block is removed that makes the structure unbalance and fall over.
  14. jwdiehl88

    Laser Surgery

    By jwdiehl88,

    Apparently, I have a mole that has a small chance to become cancerous, so I have to undergo laser surgery to get rid of the mole.  That lead to me to think, how is it possible that a laser could remove skin off a person's body, without hurting the surrounding skin.  So I learned that LASER is an acronym the represents Light Amplification by the Stimulated Emission of Radiation. So basically, lasers emit monochromatic (single color/wavelength) light that are designed to send ultra-pulses of light energy which is used to remove moles from the skin.  The heat/energy of the laser is absorbed by the pigment of the mole, it heats the mole up, and then he mole burns away.  Lasers are produced to have specific wavelengths of light that are being absorbed by certain pigment of the mole and not affect the surround skin cells.  When the laser energy is applied for the right length of time, at the right level of energy, and in the proper wavelength, the mole on the skin is selectively targeted.  This is why laser surgery is harmless to the surround skin of the mole.  
  15. jwdiehl88

    Metamaterials

    By jwdiehl88,

    Could you create an invisibility cloak?  I mean if it was possible it would be insane.  But what if there exists a material that scientist created that allows it to bend light or an electromagnetic radiation of an object, giving the appearance that it isn’t there at all.  Light is electromagnetic radiation, made up of vibrations of electric and magnetic fields. Natural materials usually only affect the electric component.  However metamaterials can affect both the electric and magnetic field.   Metamaterial is a material engineered to have a property that is not found in nature. They are made from multiple elements composite from materials such as metals or plastics.  Physicists from the UK and Germany made one small device that made small objects invisible to near-infrared radiation and worked in three dimensions.  
  16. jwdiehl88

    Mousetrap

    By jwdiehl88,

    A simple snap-back mousetrap is a clever machine. With just a few parts (a wooden base, a spring, a metal bar, and a trigger mechanism) it can do its job quickly and efficiently.  When a mousetrap is set, the spring in the center is compressed, becoming a source full of potential energy. This energy is being stored, not used, but as soon as the trap is released, it is converted to kinetic energy (the energy of motion) that propels the snapper arm forward.  This is a perfect example of conservation of energy.  It takes an amount of force to set the mousetrap and when the trap is triggered, it creates a force onto the mouse that triggered it.  

  17. jwdiehl88

    Music

    By jwdiehl88,

    Music, who doesn't like music?  Music is an universal langue. Music can be heard in any mood or activity.  It's just a thing that everyone does.  Yet how can we listen to music in general? Well sound is produced when a medium is being vibrated.  A medium could be air, water, etc... Vibrations in air are called traveling longitudinal waves, which we can hear.  The reason why sounds can't be heard in space because there is no medium where sounds can vibrate in.  Since sound can't vibrate in a medium, sound can't be heard in space.  Sound waves consist of areas of high and low pressure called compression and rarefaction. Additionally the wavelength and the speed of the wave determine the pitch, or frequency of the sound. Wavelength, frequency, and speed are related by the equation speed = frequency * wavelength. Since sound travels at 343 meters per second at standard temperature and pressure (STP), speed is a constant. Thus, frequency is determined by speed / wavelength. The longer the wavelength, the lower the pitch. Lastly the height of the wave is its amplitude. The amplitude determines how loud a sound will be. Greater amplitude means the sound will be louder. 
  18. jwdiehl88

    Opticall Ilusions

    By jwdiehl88,

    Our brain are set up to receive and interpret messages from the eye. Optics, a branch of physics, studies the interaction of the light and the eye. This interaction plays an important role in optical illusions. Optical illusions use light, colors and other features to trick the mind into thinking of things that are or aren't there. For example the Lilac Chaser Illusion. In this optical illusion, the viewer sees purple blurry dots arranged in a circle around a focal point. As you stare at the plus sign, it will appear as if a space is running around the circle of lilac discs. But after the viewer continues on staring, they will eventually see a green disc moving around the circle instead of the space. Then if the viewer continues on staring, they will then see the disappearance of the blurry dots and only see the green dot moving. We perceive movement and when we see something at one point and then at another, we believe that it is in motion. Also, when blurry objects are located in the periphery of our visual field, eventually they disappear when we have our eyes fixated on a certain spot.
     

  19. jwdiehl88
    Tennis, a difficult sport to master, has many forces and transfers of energy acting upon it.  As a two tennis players rally a ball between themselves, it seems unreal as the ball flies to incredible speed between them.  This can be explained through Newton's law as the ball exerts a force to the racket, the racket exerts the same magnitude force but the opposite direction.  Also the ball hitting the racket or the ground experiences a inelastic collision.  This is why, it is hard for tennis players to hit a fast ball coming at them and to keep it in the court.  During the contact of the ball to the racket, it loses energy and to keep the energy constant, the players has to exert energy to match the incoming ball's energy.  Additionally, it seems impossible of the speed the ball flies and the accuracy some people have to keep the ball in court and high enough to above the net.  This is can be explained of the the force of gravity on the ball as the ball flies through the air.  The force of gravity helps the ball stay relatively low near the ground then in the air.  Also for the reason the tennis ball stays relatively low to the ground, the tennis ball has a drag force resisting from the ball going straight in the air. 
  20. jwdiehl88

    Riding a Bike

    By jwdiehl88,

    Did you know that you transfer about ninety percent of your force upon a pedal of a bike into kinetic energy? Riding a bike is so simple but there is so much physics behind it. As you ride a bike there are multiple forces on you. There is a force of gravity downwards on you, so as you slow down, the force of gravity will push you and the bike down. There is also a drag force and frictional force acting on you and the bike. The drag force is the air resistance you feel when you go downhill. If you're going at a high speed with your bike then you can feel the air resisting you from going down the hill.  Also you can't forget the frictional force between the tires and the road. Then there is a force pushing you forward which is caused by the work the person does by pedaling. As the person decreases its work then, the frictional force will be greater causing the bike to slow down. But if the person increases its work, the force going forward will be greater than the frictional force causing the bike to speed up. 
  21. jwdiehl88

    Roller Coaster

    By jwdiehl88,

    Roller Coasters, how do they move so fast without any motor pushing them? Energy!  More specifically kinetic and potential energy.  In the beginning of a roller coaster ride, there is an ascension to the top of hill.  The purpose of this is that as the roller coaster gets higher and higher up, it gains potential energy.  You could calculate this by doing mass times gravity times height.  After the the roller coaster reaches to the top and starts fall down, the potential energy is then transferred in kinetic energy, which moves the roller coaster.  Kinetic energy can be calculated by doing one-half times mass times velocity squared.  Energy can never be destroyed or created so the the roller coaster has a constant energy total.  Therefore kinetic energy can be also transferred to potential energy.  This is why roller coasters can move without any motor pushing it.  
  22. jwdiehl88

    Shooting Your Grade Lab

    By jwdiehl88,

    On Friday, September 16, 2016, at 10:25 to 11:07,  Dan Fullerton presented a lab.  Unfortunately,the best 22 students of the high school, failed!  Thankfully, Mr, Fullerton allowed us to redeem ourselves by writing what the right answer was and why we failed.  This lab, Mr. Fullerton assigned to us was to shoot a projectile and predict where it would land.  By doing this we had to use kinematics.  We failed this lab for many reason. One main one was our lack of communication among our class. We didn't agree on measurements and we didn't communicate on answers. What we should of done was made four or five groups to figure out the answer and then at the end compare results.  Another reasons we failed was that we forgot to set our direction.  We didn't dictate what was positive or negative.  In our Y-component,  we assumed that everything was positive, but this was untrue.  If we made the down direction positive, then the height and acceleration is positive, however the initial velocity is negative.  Another reason why we failed, was that we had a variety of time of when the projectile was shot.
    When I redid this lab, the distance I found was 199.7 cm.  I found this by calculating the initial velocity of the X component and Y-component.  I made sure that I dictated the direction.  Then I used Pythagorean Theorem to find the initial velocity of the projectile.  Then, when Mr. Fullerton changed the angle and height of the projectile, I had to find the the X and Y velocity components.  I used the initial velocity, multiplied it by  cos (the degree) and sin (the degree).  Then I found the time in the Y-component, which is the same for the X-component.  Then I multiplied it by the new X velocity component to find my distance. 
     

     
  23. jwdiehl88

    Sledding

    By jwdiehl88,

    Sledding, a fun activity to do over the winter, applies to Newtons laws of motion.  Newton's First Law of Motion, the Law of Inertia, states that an object will not change unless it is acted on by an outside force. This means that an object at rest will stay at rest until a force causes it to move. Additionally, an object in motion will stay in motion until a force stops it.  When you are on top of a hill, there is no force pushing on you therefore you don't move. When you go down the hill, the force of gravity is on you therefore you have some velocity.  When get to the bottom, the force of friction slows you down until you stop.  Additionally, the acceleration of the sled is affected by the frictional force of the snow to the sled.  
  24. jwdiehl88

    Speed of Sound

    By jwdiehl88,

    The speed of any wave/the speed of sound depends upon the properties of the medium through which the wave is traveling.  But first if there is no medium for the wave or sound to go through, then there will be no sound.  For example, there is no medium in space so there is no waves/sounds travelling in space.  There are two factors that effect speed of sound.  One of them is the elastic properties of the medium/material.  Elastic properties of an object is how easily the object is able to bend or deform when a force is acted upon it.  So the phase of matter effects the elastic properties of the medium.  For example, longitudinal sound waves travel faster in solids than liquids and gases due to their elasticity properties.  Another factor that affect the speed of light is the density of a medium.The greater the density of individual particles of the medium the slower that the wave will be.  A sound wave will travel faster in a less dense material than a more dense material.
  25. jwdiehl88

    Swimming

    By jwdiehl88,

    Swimming is a popular sport that involves a ton of physics. The physics of swimming involves an many forces between the water and the swimmer. It is these forces which propel a swimmer through the water. In order to swim, a swimmer must "push" against the water using a variety of techniques. There are four major techniques used for swimming. They are, Front Crawl (freestyle), Breaststroke, Backstroke, and Butterfly stroke.  There are others, but ate used for recreational uses.  By moving his or her arms through the water the swimmer creates a thrust force that propels the swimmer forward.  This can relate to Newton's third law: every action as a reaction.  The swimmer creates a force in the water and the water creates a equal opposite to propel the swimmer.  However, there is a drag force created by the motion of the swimmer through the water. This force resists the motion of the swimmer through the water.  This is why, it is very hard to swim long distances because there is a friction force resisting you from swimming.  

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