Big A** Fans at Le Jardin Gym

When our Div. II basketball team traveled over to Le Jardin for a basketball game, we couldn't help but notice how breezy the gym was - until we looked up and saw the "Big A** Fans" they had on the ceiling. If we treat the fan blades as the objects going in a horizontal circular motion, we can calculate the centripetal force assuming we know the mass of the fan, the velocity at which it spins, and the length of the blades, or the radius. By increasing either the speed of the fan, or the radial distance, we can increase the amount of air that is circulated throughout the gym to keep us athletes cool as we play. Furthermore, the banked blades increase the amount of circulation possible in the gym because the normal force is broken up into components and the one pointing towards the center of the fan is the centripetal force. The bank minimizes friction and allows for the fan to spin at a greater speed.

This type of environment was much easier to play in rather than air conditioning - and probably more cost effective too. Our school should look in to getting fans like Le Jardin and Punahou rather than air conditioning. Maybe it will help us win since we won our game that day :)

Momentum in Football

This past unit in physics was all about momentum and how it is conserved between two objects during a collision. This reminded me of tackles in football (seeing as at Iolani we’re pro at football – 4peats!). Tackles are a pretty frequent occurrence when it comes to football. Ideally, when two people hit each other the momentum should be able to be calculated using the equation for the change in p: MVf – MVi(player 1) = MVf – MVi(player 2). Assuming we know the mass of both players and their initial and final velocities we can prove that momentum was conserved. Furthermore, if we assume that when player 1 makes a tackle and lands on top of player so that this is a sticky collision, we can use the following equation to calculate any of the variables or to help find the momentum: M1V1 + M2V2 = (M1 + M2) Vf. However, if the players hit each other then fall backwards, we can use the bouncy collision equation to help calculate the momentum: M1V1i + M2V2i = M1V1f + M2V2f. Anyways, way to go Raiders! :)

Blog 5: Work and Power

Now that the fall play has finished (*tear*), it is basketball season and time to get back in shape.
When playing basketball there are many instances of performing work, or Force times the change in x, or the change in kinetic energy. For example, as I accelerate while running down the court on a fast break, I can use my change in velocity and mass to calculate my total work using the equation .5mv(f)squared - .5mv(i)squared. Work is also done when I transform my energy from kinetic energy as I run to potential energy when I jump in the air to shoot, rebound, or block a shot. This can be calculated using the equation KE(ground) + PE(ground) = KE(air) + PE(air).
However, the key to being a successful basketball player is to not only do a lot of work but do it efficiently and correctly in order to out-perform the other team. In order to be successful you must be powerful. Power is how fast you do work and is calculated using the equation work done divided by time. Therefore, after I determine how much work I do while running down court or transforming my kinetic energy into potential energy by jumping straight up in the air, I can divide it by the time it take to perform the said action to calculate how powerful I am. Having to play the position of a post player or small forward, the key to my success is being quicker and more powerful than the other team even though I am smaller, so knowing my power and improving upon it as the season goes on is a must.

Here is a link to a photo in which I am shooting the game winning three pointer to beat HBA :)
http://www.printroom.com/popupImage.asp?img_id=155401118&effectRGB

Blog 3: Newton's laws of motion

One weekend before the start of school, I took my little brother and sister shopping at Ala Moana. We took a few pictures in the car on the way there, just for this blog :P

Newton’s first law of motion is the law of inertia and it states that any object will remain stationary or continue to move in a straight line unless acted upon by an external force. A car related example is when you are traveling in a moving car, you are moving in the same direction and with the same speed as the car. If the car suddenly stops, you continue moving – through the windshield if you choose not to wear a seatbelt. I promise though, as a responsible big sister, everyone in my car used a seat belt. Inertia also explains who you lean in the opposite direction when the car turns around a steep curve because your body continues to move straight during the turn.

Newton’s second law of motion states that acceleration is determined by the net force acting upon an object, and the mass of the object. By this law we can conclude that if the net force is higher, acceleration increases but if mass is higher, acceleration decreases. Another car related example is that no matter how hard my brother attempted to make the car roll forward when we stopped at a signal by rocking back and forth, the car would not budge because the car’s mass was so much greater than the force my brother was creating.

Finally, Newton’s third law of motion, the action reaction law, states: for every action in one direction there is an equal and opposite reaction in the opposite direction, even if the object in question does not move. My final car example, a somewhat lame one I might add, is that as we sat in the car, we provided a force on the seats action down towards the road. At the same time, the seats provided an equal an opposite upward force and my siblings and I.

This concludes my application of Newton’s laws of motion to my little sibling outing. Please enjoy the following photos of us being incredibly silly :)

Blog Two: A "Physical" Summer Vacation

To end this summer, my family and I took our family vacation on the Big Island at the Mauna Lani Resort and Spa. My 10 year old sister golfs, so in order to let her practice my parents took my sister, brother, and I to the keiki course at the resort. Looking back at our practice game, I realized that the course of the ball could be tracked using vectors. The ball on the tee would represent the origin and start of the vector. My siblings and I gave the ball an initial horizontal and vertical velocity as our clubs hit the ball off the tee. The vector the ball creates from the tee to its peak in the air represents the vector of the ball, and the initial horizontal velocity represents the x-component while the initial vertical velocity represents the y-component. Using this I could calculate the overall velocity of the ball by taking the square-root of the x-component squared plus the y-component squared. Knowing this would allow me to control the distance my ball would travel based on how long it is in the air. I could also calculate the trajectory of the ball, or the angle the ball creates with the ground by taking the tangent inverse of the y-component over the x-component. Had I known this when we were playing golf that day on the Big Island, I might have been able to beat my sister :P

Blog Number One: Physics in Football

On Thursday September 2, 2010, the University of Hawaii Warriors challenged the University of Southern California Trojans in the season opener. Although Hawaii ended up losing the game, 49-36, I could not help but notice how punting a football reminded me of the free-falling labs we had been doing in class. When the punter, Alex Dunnachie, kicked the football, he established the initial velocity. The ball was then, for our purposes, free-falling - only affected by gravity, thus establishing acceleration. The ball then slowly lost speed as it traveled higher about the field until velocity equaled 0 and acceleration remained constant. At this point, the ball started falling down towards the field picking up speed as it went, representing the ever increasing negative velocity value. When the Trojan safety caught the ball, both the final velocity and acceleration values became 0. Using all this information, I could have calculated the distance the ball traveled. But seeing as air resistance is not taken into account in my equation, it definitely would not have matched the yardage on the field.