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jcstack6

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Blog Entries posted by jcstack6

  1. jcstack6

    Fall

    By jcstack6,

    Fall is by far the best season. It's not too hot, not too cold and the leaves falling all around create beautiful views any way you turn. Physics is also all around during fall. To pick one example, falling leaves illustrate many principles of physics. One could pretend air resistance doesn't exist and see a leaf fall 9.8 m/s^2 in a straight line to the ground, but that would take away from the beauty of the leaf falling. One would have to include air resistance, measured by either bv or cv^2, where b and c are constants and v represents velocity of the leaf. Even the inclusion of air resistance, however, wouldn't totally explain the nature of the leaf falling. It would describe the leaf speeding up as it falls, eventually reaching a terminal velocity until it stops on the ground. The irregular shape of the leaf is what needs to be taken into account to truly define the nature of the falling leaf with physics. The irregular shape is what makes the leaf move side to side, accelerating at different rate throughout its fall. If we were to consider a ball falling, air resistance would be easy to calculate, but due to the irregularity of the leaf, the nature of its fall is difficult to explain in terms of physics. It is amazing how complex the physics is behind an object as simple as a falling leaf. 
  2. jcstack6

    Shoot Your Grade Lab

    By jcstack6,

    In a lab recently conducted by the Physics C class, Mr. Fullerton required the class to place a textbook at a location where they predicted a ball launched by a projectile would fall. The class got one test launch to observe the behavior of the projectile and then the angle that the projectile was launched at was changed and the location of the ball when it lands had to be predicted. The class failed to calculate the final location of the ball due to improper calculations, specifically not representing certain vectors with their proper direction. In the initial lab, the distance in the y direction was thought to be positive instead of negative. This threw off our calculations for the initial velocity of the ball in the y direction and therefore made our initial velocity, the combination of the x and y components of the velocity, incorrect. Since our initial velocity was incorrectly calculated based on data for the first trial, we did not have the proper initial velocity for the projectile when the angle it was launched at changed, causing us to have the wrong final answer to where the ball would land when launched from the new angle. 
    After redoing the problem and realizing what we did wrong, I came to an answer of 199.42 cm in the x direction for the distance the ball would travel in the x direction before hitting the ground. By changing the y direction value for the first trial calculation to a negative number, this corrected the initial velocity in the y direction and thereby corrected the overall initial velocity. Then when calculating the value the ball would travel in the x direction for the second trial, checking over that all vectors had the correct associated directions, the time was first calculated by utilizing the y plane using the equation dy = vt + 1/2at^2. The time found for how long the ball was in the air was .427s. The time was then used in the x plane to find the distance using the equation dx = vt. This equation yielded the final answer of 199.42 cm as the distance the ball traveled in the x direction. 
  3. jcstack6

    The Piano

    By jcstack6,

    Many people understand that the third pedal on a piano allows the notes to be held out for longer by not allowing the strings to be muffled inside, but the first and second pedals are a mystery. The first pedal is also a mystery to me so I won't discuss that one, but the second pedal makes the notes played softer. There is a fair amount of physics that goes into making this happen in a piano. To reduce the sound, the strings are lightly touched so that they cannot vibrate as vigorously, but not too much so that they are cut out. But why does reducing the amount a string vibrates reduce its volume? It is not because the speed at which the string rotates is reduced, but rather because its amplitude is reduced. The amplitude of a strings vibration is directly proportional to its volume. So as the amplitude is decreased by the mechanisms in the piano, the volume that the piano plays at is decreased. If anyone does know what the first pedal does, I am interested so leave a comment. 
  4. jcstack6

    Biking

    By jcstack6,

    Biking is one of the most electrifying activities out there. Picking up speed as you approach a jump, wondering how much air you'll get and then being launched into the air. Not many people, however, know all of the physics behind just simply going off a jump. It can be thought of in terms of kinematics by knowing the bikers initial velocity, but then one neglects how the biker obtained that initial velocity. Rather we can consider work and energy to talk about the correlation between the force of the bike, the distance the biker accelerates, their final velocity and the height they get off of the jump. Since work is equal to the bikes force multiplied by the distance the force is acting for, and since work equals the change in kinetic energy, the greater the force or the greater the distance, the greater the bikers kinetic energy. When looking at kinetic energy of the biker, we can look at linear and rotational, but for simplicity we'll just focus on linear. Since linear kinetic energy is a function of speed and mass, the speed of the biker increases, because the bikers kinetic energy increases and the bikers mass is constant. Finally, if the biker has no potential energy before the ramp, and no kinetic energy at his maximum height, we can set kinetic energy equal to potential energy, a function of height, mass and the acceleration due to gravity. Therefore, the height a biker gets is dependent on the bikers speed, but since his speed is dependent on the bikes force and distance that the force acts, the height the biker ultimately attains is dependent on the bikes force and distance that the force acts. 
  5. jcstack6

    Soun Board

    By jcstack6,

    Recently I participated in my high school's musical The Addams Family. Many times during rehearsal I would go to the soundboard to get mic'd and then have my mic checked. I never really knew what a soundcheck composed of, so I asked my friend Jack who worked the soundboard. In the simplest terms possible, one listens to the speaker/singer and they determine which frequencies sound good in the room and which sound awful. The ones that sound awful are cut out. I thought it was pretty interesting, but had no idea how certain frequencies could simply be cut out or stopped from being amplified by the mic. Then today in my Physics C class, we learned that inductors can be used to do this. Inductors store a magnetic field like capacitors store an electric field. By using LC circuits, the soundboard is able to activate certain LC circuits that cut out different frequencies from exiting the microphone. I still don't know totally how LC circuits are able to work, but it was interesting realizes a real life use of them. 
  6. jcstack6
    Most people today have iPhone's that have an immensely complex system of wires in them to allow them to function properly. They are filled with wires, small batteries and capacitors to allow for the story of data and basic functions on your phone. But this complex system presents a problem when faced with a magnet. If a magnet is brought closer to a phone it will cause a changing  magnetic field around the phone's wires. The change in the magnetic field will cause current to move in the direction opposing the change in the magnetic field. But doesn't the complexity of iPhone's help prevent this problem? Actually it makes it easier to destroy an iPhone with a magnet. Since magnetic fields can only affect current perpendicular to their direction, the complexity of an iPhone's circuits provide ample opportunity for the changing magnetic field to align properly with a coil of wire thereby inducing a current in your iPhone and destroying it. So next time you're near a magnet don't rub your phone up against it!
     
  7. jcstack6

    Ice Skating

    By jcstack6,

    When a skater goes into a spin, they usually start it with their arms out wide, spinning at a slow pace. Then the skater pulls their arms in and the speed at which their rotating increases and finally as the spin comes to an end, their arms extend again and they slow down. Many people understand that physics is incorporated in skating, but they don't understand how much goes into a simple spin in terms of physics. Rotational momentum is defined by the objects moment of inertia multiplied by their angular velocity. An object's moment of inertia is defined by their mass multiplied by their radius squared, multiplied by a constant determined by the shape of the object. Therefore, as a skater pulls in their arms, their radius decreases, decreasing their moment of inertia. Since rotational momentum is conserved during the skaters spin, their rotational velocity increases as their moment of inertia decreases. It is astonishing how simple something so mesmerizing can be after the physics behind it is understood. 
  8. jcstack6

    Resolution

    By jcstack6,

    One of the most creative sounds in music is when a composer is able to resolve a chord. The chord starts out sounding as though the pitches are fighting each other, this is called dissonance. The listener hates this sound, but it makes the resolved pitches sound even better. To resolve the chord, the dissonance is ended by balancing out the wavelengths of the pitches. This is done by changing the notes in the chord such that their frequencies create regular harmonies such as a third and a fifth. The physics behind resolving a chord is extensive, but at the same time straight forward. The frequencies of the pitches that create dissonance are so close together, almost the same, that the waves created make a sound that could be compared to the notes fighting with each other, and to some extent this is true. The pitches don't want each other to change frequency, but the listener desperately does. This is the reason why resonance sounds so good. Once the pitches stop "fighting," once the pitches frequencies are in pattern with each other, the conventional chord sounds a thousand times better being played right after dissonance. 

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