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bdavis

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  1. bdavis

    Physics of a curveball!

    By bdavis,

    I am a man who loves baseball and when i figured out that physics plays a huge role in pitching, i got excited. Physics is exhibited very well in curveballs. A curveball is a pitch that was named for its movement; it curves on its path towards home plate as it reaches the batter.

    The pitcher grips the ball on the side just over one of the seems and when he throws it, he flicks his wrist hard creating the ball to spin sideways as it travels forward towards the plate. As it shows in the diagram, the rotation on the ball creates high pressure as the seems turn over which eventually makes it turn hard and dip towards the end of its flight. The harder it is thrown, the more dropping action it will experience because the greater the high pressure will be. Hitters better watch out because physics is not on their side when it comes to hitting a curveball.
  2. bdavis

    physics of a mowhawk!

    By bdavis,

    The varsity cross country team decided to get mowhawks to get pumped up for thier sectional race this past saturday. As a member of the cross country team i got one as well. Most of our runners had long enough hair to spike it and create very large and excentuated mowhawks. I didn't have enough hair to do that so i got the sides of my hair shaved off and my mowhawk looks like a drag strip right down the middle of my head. This type of mowhawk has some very unique properties. As a runner, i want to maximize my time. My type of mowhawk provides less air resistance that would be provided by my hair. With less hair on the sides of my head, the air can move past my head easier and the strip in the middle of my head can help to split the air on either side of my head. Therefore, when running, a mowhawk may look kind of dumb if the person can't pull it off but it can help improve a runners times on a day where head wind is a problem.
  3. bdavis
    In our everyday world, mechanics that work with cars in autoshops work with a physics concept that we all know and love: Torque! Cars are working machines that are assembled by many parts and those parts are held together by bolts and screws and lug nuts. Tools such as wrenches and pliers allow mechanics to secure parts by putting the nuts and bolts on the car.



    Torque is equal to the applied force times the radius or length from the fulcrum of the object. (T= Fr) To ensure that a lug nut stays on the part of the car and stays there, a wrench should be used.

    To apply a greater torque, a longer wrench should be used when repairing a car. In an experimental setting, a mechanic may want to pick the best wrench to ensure that a lug nut is securely fastened on a part in the car. If he applies the same force to the end of each wrench, would he be better off using a 18 inch wrench or a 12 inch wrench? Well, the equation shows that if the force is kept constant, Torque is directly proportional to the length of the wrench. The longer the wrench, the greater the torque if the force is kept constant.

    So in the future, if a lug nut isn't staying properly fastened on your car, using a longer wrench may be very helpful.
  4. bdavis

    physics of body building!

    By bdavis,

    Many people might not think it but the meat-heads who body build conduct physics related actions everyday when they go to the gym. The weights they lift are objects that apply a force to the muscles that are targeted in different exercises. Newton's second law, net force= mass x acceleration (F=ma) shows that force is equal to the mass times the acceleration. So the weights that people lift when they work out have a mass that is accelerated by gravity to produce the force overcome by muscle movement. Building muscle mass can be attributed to Newtonian laws of Physics!
  5. bdavis
    Ever since i saw my first Jackie chan movie (which i cannot remember off the top of my head), i have always been curious how a man, not especially strong and bulky with the muscles most football players possess, can break a cinder block in half with his bare hands. I previously thought that the cinder block would be too strong for even the most muscular man to even crack it let alone break it.



    In this video, the person had two thick bricks stacked on top of each other and he broke both of them simultaneously with his bare hand. He put the very edges of the bricks on blocks so they would provide a very minimal normal force in the opposite direction of the applied force of the karate chop. Also, he aimed at the middle of the block with his applied force to where the center of mass had the greatest force in the downward direction provided by gravity. Therefore, when the man made contact with the block, the block was subjected to the force of gravity down and the applied force of his chop. With no reinforcement below the middle of the block, the person applying the force will feel a minimal normal force applied by the block itself. A very large force must be applied by the person chopping at the block but with the assistance of gravity and no reinforcement under the block, breaking a brick with bare hands is easier than it appears to be!
  6. bdavis
    Now it may seem like I am running out of ideas but planting a flower incorporates an important physics concept. When removing a flower from its packaging, a proper amount of force must be applied. If too much force is applied when removing a flower from its packaging, then it will therefore accelerate too much and the roots at the bottom of the package will separate, killing the innocent flower. When actually planting the flower, after digging an appropriate sized hole, you don’t need to shove it into the ground. By gently placing the flower into the subsequent hole and covering the surface with dirt is the first step to execute. Secondly, a firm yet gentle pressure must be applied to pack the soil down on top of the flower so the roots and stem are secured. If too much pressure is applied on such a small area, it will experience a greater force, thus accelerating into the ground more and crushing the roots. The stem will therefore become unstable and fall over. The flower will then shrivel up shortly after. In gardening, a lot of finesse is required so as to not kill the flowers. These two equations (force equals pressure times area and net force equals mass times acceleration) show how and why too much applied will harm the flower.
  7. bdavis
    Yesterday in class we learned about Einstien’s theory of relativity and time travel. Our physics teacher explained to us how traveling in space or being on another planet can alter the amount of time you feel and your body experiences. If someone is in Space for 70 earth years, their body doesn’t age those 70 earth years if they are far enough away from the Earth’s atomsphere. We also learned about how the speed of light is the fastest speed that can be achieved in the universe: 2.998 x 108 m/s. We discussed how no object in the universe can attain that speed because as an object moves faster, it gains mass. The more mass it gains, more force is needed to accelerate the mass to continue increasing its velocity. No matter how small the initial mass is, it will become so big that there is not enough energy in the universe to apply a force strong enough to accelerate it to the speed of light. Furthermore, we also learned about how string theory applies with electron transfer. In theory, two electrons next to each other are connected by a “string” and they have opposing spins because no two electrons can spin in the same direction when they are next to each other. When one flips, the second one is supposed to instantaneously flip as well to maintain the different directions they spin in. It has only been proven to be true at a maximum of 13 miles across a river in Russia but physicists are still working on it. I find this concept fascinating and I really would like to know more about it.
  8. bdavis

    Shocking!

    By bdavis,

    Last year, i was blow-drying my little sister's hair and when i put the blow-dryer into the outlet, i got shocked. When i inserted the plug into the outlet, i accidentally put my finger too close to where the circuit was completed. I then realized that i completed a circuit when i plugged in the hair dryer. I did a little more research. I found out that the voltage of an outlet in a home is 120 Volts. Then i did research to find out the resistance in the blow-dryer. The blow-dryer i used had a resistance of 6 ohms. Using the equation I= (V/R) (I being the current, V being the voltage, and R being the resistance in Ohms), i found out that i was shocked with 20 amps of current. I went further to calculate that the Power generated in that circuit, from the equation P=(I*V) was 2400 W of power.
    Curcuits can be simple or complicated and they can generate a lot of current and power. I am glad that i wasn't hurt because if the voltage was greater and the resistance was smaller, i could have been in quite the predicament.
  9. bdavis

    Skiing!

    By bdavis,

    One activity i love to do is ski. I love the exhilarating feeling of going really fast down a steep incline. But in order to attain a fast speed, one must have good form to minimize AIR RESISTANCE. If someone were to go down a steep trail with their torso revealed with their arms extented out, they will reveal a ton of surface area and thus, the air will have more to make contact with. In turn, that person will not go as fast as they possibly could.

    But if someone has good form that can minimize air resistance, such as tucking their arms and shoulders in and crouching down so less of their body is exposed to headwind, then they will be able to go a lot faster. The air resistance will be reduced and their speed will increase. My knowledge of physics can help me improve my speed and time down the mountain. i knew there were reasonable applications for physics!
  10. bdavis

    Spitballin

    By bdavis,

    So when my family goes out to restaurants, my mom and i take the straws they give us, rip off the top part of the paper and shoot them at each other. We also make spitballs and fire them at each other at will before we receive our food. This relates to a lab we conducted in our Physics C class. We blew projectiles from straws and then blew those same projectiles through straws that are connected to other straws. Those projectiles traveled faster and farther. Velocity is calculated by dividing the displacement by the time the projectile traveled that certain distance. (V= (disp/time)) Also, the longer the straws were, the longer the constant force was applied to the projectile. The longer a force is applied on an object, the faster it will go and therefore the farther it will travel. That is how my mom and i make it interesting: we put many straws together to make the spitballs go faster at each other. Physics is clearly involved in even the most immature behaviors.

  11. bdavis
    On may 13th 2013 I sat down in my high school in the afternoon for my AP Physcis C exam. The first test I had to take was the mechanics exam: 45 minutes for the multiple choice and 45 minutes for the free response questions. The 35 question multiple choice part of the exam wasn't all that difficult but a bunch of problems took a long time to figure out. I didn't finish that part of the exam so I had to guess on the last 4 questions. The beginning of the free response section began with a air resistance question. The week before, my physics teacher suggested we review how to do air resistance because he thought there might be one question on the test where we would need that information. I didn't heed his warnings and advice so I didn't review it as much as I should have. I was able to answer most of the question but not to the extent I would have hoped to. The last two problems were very do-able and I was able to finish the mechanics free response questions.

    The electrostatics and magnetism section of the exam was a bit more difficult in my opinion. The multiple choice section required a lot of work to be calculated and figured out by hand so again, I wasn't fortunate enough to finish: I had to guess on the last 5 questions. The free response questions only got worse. The first and third free response questions were do-able and I thought I did very well overall on those two but the second one was nearly impossible beyond the second part of that question. I finished most of that part but there were definitely some aspects I didn't understand as well as I probably should have.

    The Physcis C AP was very difficult and I am very nervous in anticipation to see what my scores are.
  12. bdavis

    The class so far

    By bdavis,

    So far for me, Physics C has been a challenge. There is a lot of information to learn and a lot of abstract ideas that I have difficulty wrapping my head around. Despite the many difficulties, that i know most of my fellow classmates are experiencing simultaneously, i find this class extremely rewarding. I have learned so much not only about physics but how to properly study and learn complex information accurately and effectively. I also find the content very interesting. So many things happen all around us everyday and i find it very interesting that we can find out how and why things happen. I am a very inquisitive person so i value this information. However frustrated i may get with the difficulties, i know that nothing in life that is worth learning comes easy and properly studying is a skill i will take with me through my travels to higher education. So i am excited to continue this course into the next semester.

  13. bdavis

    The class so far

    By bdavis,

    So far for me, Physics C has been a challenge. There is a lot of information to learn and a lot of abstract ideas that I have difficulty wrapping my head around. Despite the many difficulties, that i know most of my fellow classmates are experiencing simultaneously, i find this class extremely rewarding. I have learned so much not only about physics but how to properly study and learn complex information accurately and effectively. I also find the content very interesting. So many things happen all around us everyday and i find it very interesting that we can find out how and why things happen. I am a very inquisitive person so i value this information. However frustrated i may get with the difficulties, i know that nothing in life that is worth learning comes easy and properly studying is a skill i will take with me through my travels to higher education. So i am excited to continue this course into the next semester.

  14. bdavis

    The Cross Product

    By bdavis,

    At the beginning of the school year, we learned the two forms of vector multiplication: the dot product and the cross product. The more intricate of the two, the cross product, comes into play in many equations to provide very useful information. For example, in magnetism, F=I(BXL). This means the magnetic force is a vector cross product of the vector of the magnetic field crossed with the length of the object multiplied by the current flowing through that object. The resulting force will have values in the X, Y, and Z directions, indicating which plane the force is in relative to the length and the magnetic field. The Cross product is very helpful in revealing the direction and magnitude of the vector in that direction. It also helps to visualize where the other vectors (that influence the value of the resultant vector) are and what direction they are traveling in. Unlike most of my classmates, I like the cross product and although I don't have a firm understanding of it yet, I will continue to work on it so I can use it to better understand physics concepts as I take higher level physics courses.
  15. bdavis
    In both physics and chemistry, u, stands for a lot of things. u is the coefficient of friction, with subscripts indicating kinetic or static friction. It is the permeability of free space. It represents a magnetic moment. It indicates a micro unit (10^-6). It represents linear density. In chemistry, it represents velocity. u is also used to represent values in music, pharmaceutical sciences, computer science, software design, meat science and linguistics. Understanding each and every representation of u can be very difficult and many of the values produced do not require units so to an untrained eye, the value of u could mean many different things. Thus it could be interpreted in the wrong way. There are many other Greek letters that can be used to represent values in all fields of study so instead of overusing u, other unused Greek letters should be incorporated. As a student who has to discern between five different representations of u, it becomes difficult at times if the topic at hand isn't 100% clear. So i believe u shouldn't be used as much and other Greek symbols should be incorporated into these diverse fields of study.
  16. bdavis

    world series fun!

    By bdavis,

    So the world series for baseball happened not too long ago and something amazing happened. Hunter pence, an outfielder for the San Francisco Giants, broke his bat when swinging at a pitch but his bat hit the ball three times after he made initial contact.


    http://www.youtube.com/watch?v=mOkbQVsIk_0

    The ball made contact with the bat initially a few inches above the handle where he was holding it. In the video, you could see that the bat bent out as it was breaking and began to bend towards where the ball came off the bat. The bat and the ball collided in midair after initial contact and touched three times total. The physics involved with that is that the ball was traveling at such a high velocity and the bat was moving at a high velocity in the opposite direction, the bat couldn't withstand such a great force and it broke on contact. But the ball caused the bat to continue in its path towards the left where the ball was heading because it bent the bat on contact as it broke. Both objects were moving with the same speed coming off the bat and that is why they made contact a few more times. That doesn't happen often. The ball has to hit the right spot on the bat and the angle of trajectory of both the broken bat and the redirected ball have to be really close if not the same. If the bat was as light as the ball, they would have traveled together longer but the bat decelerated faster than the ball did due to higher air resistance caused by more surface to be exposed. Baseball has more physics involved than i realized!
  17. bdavis
    Our year has come to an end. College is in the near future and rapidly approaching with each passing hour. At the beginning of the year, I walked into physics c excited but not really sure what to expect nor was I sure how difficult the material would be. As the year progressed, I realized that the tests were hard and I needed to study harder than I ever needed to before. After I failed two out of the first four tests, I was motivated to do well on the next one. The first rotational exam came and I got the highest grade in the class. I proved to myself and my classmates that I could excel if I put the work in. The rest of the year I did decently on the remaining tests and spread my attention towards my other AP classes as well. Electrostatics and magnetism in the second half of the year was very difficult for me. I tried extremely hard to grasp the vague concepts; visualizing the actions of subatomic particles was difficult but by the time the AP exam came, I felt like I understood it better than I ever had. Going into college, I hope to take more physics courses because it intrigues me. But at the same time, I will also take the lessons I learned with me: don’t procrastinate, read the text book, ask a lot of questions, and take the initiative to study a little each night before each test so I don’t stress myself out and go into each test confident and prepared. College will be hard but I am ready to work hard in order to achieve the success I envision. I will discover the cure for cancer, buy my physics c teacher a silver Porsche, and I am ready to take the next step in education and in life.

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