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goalkeeper0

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Blog Entries posted by goalkeeper0

  1. goalkeeper0
    While some are contemplating the end of the world, I am studying for physics. Here are the essential oscillations equations to know for our test tomorrow.

    Oscillations (Includes SHM, Springs, Pendulums):

    F=-kx
    xmax=A
    vmax=Aw
    amax=Aw2
    T=1/f and f=1/T
    w=angular frequency=2(pi)f=2(pi)/T
    v=wr
    Potential Energy= (1/2)kA2cos2(wt)
    Kinetic Energy= (1/2)kA2sin2(wt)
    Total Energy= (1/2)kA2
    x(t)= Acos(wt + phase shift)
    v(t)= Awsin(wt + phase shift)
    a(t)= -Aw2cos(wt + phase shift)
    Tspring= 2(pi)[m/k]1/2

    For use with pendulums only:
    Tpendulum= 2(pi)[L/g]1/2
    w=[(mgL)/(Ip)]1/2
    w=[g/L]1/2

    Also, from past units, the torque equations are handy, along with the moment of inertia equations.

    STUDY!!!
  2. goalkeeper0

    Weight loss solution

    By goalkeeper0,

    Around the holidays, people typically gain weight as cookies, candy canes, and other treats are around every corner. But, this Christmas, you can lose weight! Without a diet, and without exercise, there is one answer to the essential question: "How can I lose weight?" Simple. Go to the moon.

    Here is the calculation to prove this solution really works!

    1) Find g:
    g=[G(mass of moon)]/[(radius of moon)^2]
    g=[6.67x10^(-11) x 7.35x10^22]/[(1737000 m)^2]
    g=1.62 m/s^2

    2) Convert your weight from lbs to kg
    130lbs=59 kg

    3) Weight (N)=mg
    Weight = 59 kg (1.62 m/s^2)
    Weight on the moon= 95.58 N

    So, what do these results mean?
    Your weight loss can be measured in Newtons as you went from about 579N to about 96N. Or, in lbs, you went from 130lbs to about 22lbs!
    On the moon, you weigh approximately 17% of your weight on the earth.
  3. goalkeeper0

    Oscillations Review

    By goalkeeper0,

    As we are in our second independent unit, I thought I little review picture couldn't hurt. Remember:
    1.) Max acceleration is achieved when the spring is at -amplitude or +amplitude.
    2.) Max velocity is achieved at equilibrium.

    And, along with this, we must know:
    KE= (1/2)kA2sin2(wt) w= angular frequency, k= spring constant, A= amplitude, t= time
    PE= (1/2)kA2cos2(wt)
    These equations are useful when finding the Potential or Kinetic Energy at time, t, in the oscillation.
  4. goalkeeper0
    Every high school student treasures his or her first college letter in the mail. However, when the letters begin to consume your recycle bin, they become overwhelming. Each letter seems to advertise the same things: a nice campus, low student:teacher ratio, updated infrastructure, and groundbreaking research. So, when something different comes in the mail, it is exciting. Recently, I received a letter from the University of Akron advertising their Corrosion Engineering major, which is not offered anywhere else. As many of us taking AP Physics C intend to become engineers or scientists, I thought you may be interested in learning about Corrosion Engineering.

    *Corrosion engineers learn how to reduce the costs or corrosion, and design structures (roads, bridges, etc.) for greater performance and safety.
    *Currently, corrosion costs the US around $400 billion a year. Rusty columns, bridges, and pipelines are threats to society. Corrosion engineers work to improve public safety by assessing the damage done by corrosion, and slowing down the process of corrosion.
    *Corrosion engineering blends together chemical, electrical, civil, environmental, and mechanical engineering.
    *The demand for corrosion engineers is extremely high, as the US infrastructure continues to age.
    *Both the government and industries have donated large sums of money to this program at the University of Akron. Recently, BP donated $500,000. The major is up-and-coming.

    This is just a brief description of corrosion engineering. Overall, it seems like a great major if multiple branches of engineering interest you. Also, the job stability is tremendous as the instability of US infrastructure increases.
    If you want to learn more visit http://www.uakron.edu/corrosion/academics/curriculum.dot.
  5. goalkeeper0

    Black Friday Tips

    By goalkeeper0,

    As Thanksgiving is just around the corner, retail stores are bombarding consumers with Black Friday ads. The ads show glittery, appealing products at low-prices. But, what the ads do not show--crowded parking lots, irritated customers, and stampedes-- you must watch out for. To minimize your risk of injury, here is some physics advice if you are one of the bold buyers who battles Black Friday crowds.

    1) Attempt to maximize your power (force dotted with velocity) beforehand. A balance of force and velocity is necessary. Do not bulk up, because your velocity will suffer, and you will be at the back of the crowd. However, if you are relatively mass-less, but fast, you will also be at the back of the crowd.

    2) Bring along a friend! With a friend to help carry your purchases, more work can be done. As work is force dotted with displacement, lifting heavy boxes, pushing televisions, etc. will be much easier with the help of an assistant.

    3) Avoid stores where a wide waiting area slims down to a narrow entry. Why? Conservation of flow rate. Flow rate= Area of space for people x velocity of the crowd. Therefore, when people head toward the doors, the velocity of the crowd must increase as the Area of the space decreases, to conserve flow rate. This means that as you approach the door of the store, the speed at which people are "flowing" increases. This is how many stampedes occur.

    All in all, if you do venture outside in the wee hours of the morning, fuel up! Eat healthy foods beforehand to give your body the necessary potential for success.:eagerness:
  6. goalkeeper0
    Opening a fresh jar of pickles can be challenging. If you are somebody who struggles opening jars, don't be discouraged, physics can help. If you run the jar under hot water, the lid will become easier to turn. But, why? Metal has a higher coefficient of expansion than glass does. So, as the jar stays under the hot water, the metal expands a tiny bit, and the glass stays the same. There is no longer a need to workout, just run your tricky jars under the faucet, wait a minute, and let physics take care of your problems.
  7. goalkeeper0

    Fork trick

    By goalkeeper0,

    While I was dutifully studying physics today, because we are in our independent unit, I remembered the experiment Mr. Powlin did last year with the forks and toothpick. This experiment shows the concept of center of mass quite nicely. First of all, center of mass is the point on a system that moves as if all the mass of the system were concentrated at that point, and all external forces acted only on that point. In the magical experiment Mr. Powlin did last year, he shoved two forks together, so that they were connected between the tines. Then, a toothpick was wiggled between the forks. The toothpick was then balanced on a drinking glass, and the forks seemed to hover. The end of the toothpick between the rim of the glass, and the center of the glass, was burned. And, the toothpick ended up just barely balancing on the rim of the glass. Meanwhile, the forks were still attached to the toothpick. Why don't the forks fall? The center of mass of the toothpick and fork system is right below where the toothpick rests on the rim. Therefore, the system is in equilibrium. So, in the end, physics can explain this magical trick.

  8. goalkeeper0

    The WindTamer

    By goalkeeper0,

    When an adventuresome IHS student ventures out of the school building to the turf field, he or she passes the WindTamer and solar-powered lights. I do not know how much energy the turbine actually harnesses, but it is cool nevertheless. How does the WindTamer work? The WindTamer turbines create two vacuums which suck air through the blades, and the blades rotate (creating rotational kinetic energy). One of the vacuums is behind the blades, and the other is behind the turbine. The blades used in the WindTamer are very light, but numerous to produce the optimal amount of energy. The light blades move with the slightest amount of wind; so the device never wastes wind. The WindTamer definitely did not waste any wind this past week with Hurricane Sandy in town! It delights me that the engineers of the WindTamer took the wonderful birds of Irondequoit into account. The shape of the WindTamer, with housed blades, is supposed to reduce the amount of birds which fly into the device. If any brainless birds still fly into the WindTamer, natural selection is simply taking its course.

  9. goalkeeper0
    In class today, while doing the preliminary questions to the lab, we debated whether a clay or rubber ball, of equal mass, would push a door closed more. At first, I thought that the clay would close the door more; but, since the masses are equal, I rethought my intial response. The question is basically asking which medium will create the greatest impulse. Because the clay sticks to the door, the collision is inelastic, and energy is lost as the clay sticks to the door. Because the rubber ball bounces off the door, the collision is elastic. Kinetic energy is conserved for elastic collisions, and the change in velcoity is greater (impulse=m(change in velocity)). So, the impulse is greater with the rubber ball.

    [ATTACH=CONFIG]508[/ATTACH]I found this picture online which helps to explain the elastic collsion in this problem.
  10. goalkeeper0

    Catapult

    By goalkeeper0,

    This is a picture of our beautiful catapult. The potential energy of the garage springs was converted into the kinetic energy of the arm. We positioned the beam across the catapult at about a 45 degree angle with the base. This angle maximized the range of the softball. For our first two launches, we had padding on the center beam, to absorb a bit of the kinetic energy of the arm, so the wood wouldn't break. But, for the third trial, we took off the padding, and the wood ended up cracking. The metal attachment on the arm also bent. After completing the calculations associated with the catapult project, the total initial velocity of the projectile was 17.96 meters per second, and it took 1.135 sec for our catapult to reach maximum height.
  11. goalkeeper0
    This weekend, my brother was flipping through the TV channels, and a very interesting sport came on. The Dutch sport of Fierljeppen, similar to pole vaulting, involves a person sprinting, jumping onto a long pole at an angle, climbing to the top of the pole while it tilts over, and hopefully landing on sand on the other side of a pond. This sport is also known as canal jumping, as the athlete clears a body of water. In terms of the energy of Fierljeppen, here it goes. A person of mass, m1, and velocity, v1, applies a force to an angled pole of mass m2, and an initial velocity of zero. When the athlete grabs onto the pole, the kinetic energy of the athlete is converted to potential and kinetic energy of the system (athlete and pole become a system of mass (m1+m2) until the athlete releases the pole, and lands in the sand). As the person climbs up the pole, the kinetic energy decreases, and potential energy increases to the 90 degree point. It's basically free fall from that point. Hopefully the sand is deep, and the pole doesn't break!

    Click on this link to watch this peculiar sport.


  12. goalkeeper0

    Physics News Alert

    By goalkeeper0,

    This is my first blog post with nothing to do about soccer! Tonight, when my dad was reading the Democrat and Chronicle, and I was doing my Calculus homework, he read me a blurb about an American and French Physicist who just won a Nobel Prize in Physics. The paper didn't explain much of anything in terms of what these physicists did to merit the prestigious award. I think the brief description was because the physicists, Serge Haroche and David Wineland, studied quantum physics and applications between quantum physics and computers. I do not think many people would actually understand what these men did if the newspaper went into further depth into their research/studies. I tried to understand the breakthroughs these men made in the physics world. So, I looked them up online and found this website, http://www.pcmag.com/article2/0,2817,2410825,00.asp. I learned that they separately studied interactions between light and matter. In particular, Wineland's work made strides toward the first "quantum computer," which would run much faster than a normal, digital computer. Wineland and his research team also created a clock that is one hundred times more precise than the most precise clocks we use today for the standard of our measurement of time. Wow.
  13. goalkeeper0
    A couple games ago, my soccer team had ample opportunities to score against Gates Chili. We managed to sky the ball over the net from the six yard line, in the first five minutes of the game. After thinking about how hard it is to miss the goal from this distance, I thought I would compute the angle, theta, needed to clear the crossbar (8ft off the ground) from the 6-yard line.
    Given: *average velocity of shot ~45ft/s
    (this value varies between male/female, and level of play)
    *delta x=18ft
    *delta y=8ft *g=-9.81 m/s2=-32.12 ft/s2


    Find time in terms of theta: delta x= (velocity in x direction)(time)
    time=(18/(45cos(theta))) s

    Find Minimum Theta: delta y=(V-initial in y direction)(time)+(0.5)(g)(time)2
    8=18tan(theta) - (2.57/cos2(theta))
    Solve for theta and get.....
    theta must be greater than 32.9 degrees to miss the goal.

    Conclusion: Given that the ball is kicked around 45 ft/s, 32.9o< theta <90o would cause the ball to go over the crossbar!
  14. goalkeeper0
    Yesterday, the Girls' Varsity Soccer team started out with our first win! We scored a late goal with less than 2 minutes left in the game to make our way into the finals (of the tournament) on Saturday. After the celebrations and high fives, the referee came up to me and asked, "Have you taken Physics?" A bit taken by surprise, I responded "Yes." She went on to compliment the power and velocity of my punts, but she questioned the height. She believed, given the power behind the punts, that they should have greater horizontal range, and lower vertical distance. The ref believed that if I lowered my body, decreasing the projection angle, my punts would fly much past fifty yards. Her advice made me wonder, Is there an optimal projection angle? I looked online and found a study done in at Brunel University in the UK. Two men researched, and experimented to find the optimum projection angle to achieve maximum distance on a punt. To do this, they also took into account ball spin rate, projection height, projection velocity, foot velocity, and many more factors. What were their findings? To reach his or her maximum range, the average goalkeeper should have a projection angle of around 50 degrees. I definitely want to attempt this; but, the exact measurements might be a little tough, without the necessary technology. In practice, I will just experiment with many different projection angles.

    To read more in depth about this, I found the results of the study at Brunel University on http://www.jssm.org/vol10/n1/27/v10n1-27pdf.pdf.
  15. goalkeeper0
    So, this first blog entry is an introduction to me, goalkeeper0. As seen in my username, I obviously am a goalkeeper (for soccer)...I will soon post a blog entry about a recent soccer/physics encounter of mine. So, about me. I am interested in a combination of all three sciences, Biology, Chemistry, and Physics. Thus, in college, I hope to study biomedical engineering-- which brings together both engineering and medicine. Biomedical engineering appeals to me, because of its many different career paths, whether that be in imaging, regenerative medicine/tissue engineering, work with prostheses, etc. Originally, I was just going to take AP Chem this year, but I really wanted to take Physics C too. After reworking my schedule, I added Physics C, because I want a strong Physics background going into college. Plus, I like taking challenging courses. Last year, I enjoyed AP Physics B a lot more than I thought I would, and I look forward to learning Physics with Calculus. By the end of the year, I hope to be a confident physics student. I look forward to learning with you all (fellow Physics C students)! What am I most anxious about? Well, I really don't know yet. But, as soon as we get deeper into Physics C, I bet I will be anxious about pretty much everything...but I suppose that is normal.

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