Top Ten Blog

I am an Asheville School tracklete and have competed in long jump, triple jump, discus, shot put and various sprints. In order to better improve my performance and compete more efficiently, I often use laws and concepts of physics. (Rotational inertia) My favorite event to compete in is the discus throw. The discus throw relies on rotational inertia. In order to stay under control in the early spin phase I extend my leg out far when spinning. The leg extension changes the distribution of my mass over my center of rotation and this increases rotational inertia so I can enter the spin in more control. In the second phase in which I throw, I pull my leg inwards so my rotational inertia decreases causing a quicker rotation, allowing me to get off a harder throw.
     (Center of gravity/base of support) When sprinting I want to be able to accelerate as quickly and much as possible. So to increase the quickness of my acceleration I use block starts. Block starts are tilted steps that put your center of gravity over your base of support. This allows you to start moving  because you will feel the force of falling due to your COG being over you BOS, and this force of falling will propel you forward much faster than starting while standing up.
     (Falling objects) When competing in the long jump you want to run and jump as far into the pit as you can. But what controls how long you are able to carry that force from running into the air is height. Height controls how long you will stay in the air an fly forward into the pit. So as I learned early on, I would need to jump a high as I possible could so I could have more time in the air to collect more distance into the pit. So instead of focusing on  horizontal distance I focused on vertical distance and this improved my jumps significantly.
     (Projectile Motion) When throwing an object it will maintain the same horizontal speed but will have a changing vertical speed. Which is why it is important to get as much force behind a shot put when throwing. The perfect angle to throw a shot is 45 degrees and you want to get strong horizontal speed behind it so It is able to cover the greatest amount of distance possible before it hits the ground  Here is a picture/gif of how a shot put should look while in air.
     (Kinetic Energy) I never competed in the pole vault but I understand how the concepts of physics rules the sport. In pole vault you want to run as fast as possible to create a large amount of kinetic energy. Kinetic energy is .5mass x velocity^2. The mass is the pole vaulter and the velocity is how fast you run up. Using this equation we find that the faster you run, the higher the kinetic energy and kinetic energy transforms into potential energy which is connected to height, so the more the kinetic energy, the more the potential and therefore the higher you go.
     (Newton's 3rd Law) Each action has an equal and opposite reaction. When sprinting you want to drive far as fast as possible. And when running we push the grounds backwards and the ground pushes us forwards. So to sprint fast we must push the ground fast and hard so that the ground pushes us back fast and hard forwardly. So sprinters when running, run very hard on the ground in order to utilize newton's 3rd law and receive a strong fast reaction to push them fast.
     (Power) High jump also relies on the physics concept of power. Power is work over time. And work is force x distance, but in the case of jumping the distance put in isn't to important to the application of physics. In order to create a mass amount of power to launch oneself into the air, they must apply a huge amount of force over a tiny time period. And when high jumping you want to run up and gain strength, drive that strength hard into the ground in a very quick time interval so that your power in that split second is greater than your weight which will launch you in the air. Here is a video explaining this process...
  
   (Axis of rotation) A high jumper also must be conscious of their axis of rotation while in air. If their axis of rotation is over the bar you can't jump over it, the video highlights the importance of keeping your axis of rotation under the bar to keep you from crashing into the bar. You can do this by arching your back.
   (Torque) When running we all pump our arms right leg-left arm and left arm -right leg. We do this because bringing our leg up creates a torque and we balance this torque out with lifting our opposite arm. Tracks are rounded so while running the curve we have to adjust our direction to stay in the lanes and in order to maintain equilibrium in this action, we lean our torso towards the curve. All of these motions counteract the torque.
     (Friction) To move anywhere there must be friction. If surfaces were frictionless there could be no self propelled movement. So if friction helps create movement, a lot of friction must create faster movement. This is why I wear spikes. Spikes allow me to create a lot of friction with the ground and move quickly because of it. The friction keeps you stable and the spikes keep you on your toes, and when on your toes running you are leaning forward keeping your center of mass over your base of support giving you a stronger force in the forward direction. 

Wind Turbine

Before diving into a project like this, one would need some knowledge of electromagnetic induction. If not you will surely fail because this is the primary concept we used to create the maser piece of our wind turbine. Electromagnetic induction requires a magnet, coiled current carrying wire and source that collects current. When a magnet passes through the wire coils there is a current induced to the wire. And for our wind turbine we used four tightly coiled wires for a current to be induced in. Here is a picture of our set up below.

In order to induce a current through these wires we needed our magnets to constantly be passing across these coils. And because would have the aid of wind we decided to have our magnets on a platform that would spin due to the wind rotating it. Our set up for this is below. 

So the magnets were set upon a spinning top, so that the wind would rotate this circle and keep the magnets passing through the coils. The magnets were also placed to directly line up with the coils so there was and equal passing through of coils. Ok now we have the two components that have potential to create a current. All we need now is something to catch the wind and rotate the magnet platform. So we used a water bottle to catch the wind from the fan and we built it so that no air would be wasted. Our wind catcher looked like this

When the bottle caught the wind the magnet base rotated over the coils and caused induced voltage through the wires and created current. All together this process ran pretty smoothly and looked like this...

Our wind turbine was able to generate .01 amps. Which is ok but not enough to light a light bulb... bummer! We would need much more ampage to light a bulb and to do this we could maybe create a stronger wind catcher. After this project I learned that the wind catcher is very important in creating voltage. Other turbines that had two wind catching fans created significantly more voltage than turbine like mine. Maybe this caused more rotation over the wires. But we went into this project with a well devised plan and everything worked well the first time. We did not have to try anything over, or remake any parts of the turbine, we learned from the last project that slow and steady crafting wins the race so we took our time compiling the materials. If I could do this project again I would probably change up the wind catching machine into a bi wind catcher in order to generate more voltage. 

Unit blog magnets

This unit was about magnets. We began by learning about the anatomy of magnets. The source of all magnetism is moving charges. There is a north pole and south pole in a magnet and the magnetism flows from north to south and opposite poles attract. But the poles of earth are quite deceptive. The north pole on earth is actually the magnetic south pole, oh yeah and earth is a huge magnet. The magnetism of earth causes strange events like the northern lights. We then learned about forces on a magnetic field, we easily memorized the directions of forces, currents and magnetic fields using the right hand rule. We reinforces the concepts of forces on a magnetic field by creating a motor. We had a battery with a magnet, paper clips and a current carrying wire. We wanted to convert electrical power into mechanical energy. Here is the video of my motor

 

We were able to redirect the force upwards using the right hand rule and move the current carrying wire in rotation. The current moved side to side and the force moved up rotating the wire up. We then learned about electromagnetic induction. When a magnet runs through a coil of wires a current is induced. Traffic lights and credit card readers utilizes this. The cars a magnets and there are coiled wires connected to the light right by the stop. We reinforced this knowledge with our wind motor project.

The process of turning AC current into DC current is creating a generator. The number of coils can change the voltage put into the source. Decreasing the coils in the second set increases the voltage and vise versa, it's directly proportional. When the number of coils in the system are two different numbers that is making a transformer, this way only a certain voltage and current gets to an appliance for safety reasons.