Okay, so my house doesn't actually have yellow walls and orange carpeting, but i couldn't find the right colors on paint. Anyway, since we are learning about torques now, i began to notice naturally occurring torques in my house. I was lying down diligently studying from my US history book when my little sister and my dad walked into the room. My dad went to the window to open the blinds and let light in. It just so happened that at the same time, i was turning a page in my book and my sister left the room again (plus, the fan was on). In that instant, there were five torques being exerted on different objects. The chain my dad was pulling to open the blinds exerts a torque on each individual vinyl panel that makes it rotate, letting light into the room. My sister exerts a torque on the doorknob to turn it and a torque on the door itself to close it behind her. The fan exerts a torque on each of its blades to rotate them, and finally, i exert a torque on the page of my book to turn it. fin.

The other day i was riding my bike down to my friend's house to watch the UH football game. When i rode my bike down the street the road was dry and the sun was out. By the time the game was over, however, the sun was down and the road was wet with rainwater. As i was headed home i didnt see a big puddle of water in the middle of the street. I rode right through it and to my surprise my back felt wet through my tshirt. When i got home, i looked in the mirror at the back of my shirt and there was a fat line of water going up my spine. The water flicked off my back tire and up onto the back of my shirt. This made me think about what Mr. Kohara said in class. The water could not stay on the tire because a sufficient amount of friction did not exist to hold the water onto the tire. Therefore, the water shot off tangent to the tire and landed on my back. If i rode through the puddle more slowly, however, the water would not have flicked up onto my back because of two reasons: 1. the amount of centripetal force needed to keep the water on would be less because of a slower speed and 2. more water will have fallen off the tire before it could get up to my back.

I was at Troy Todd's house on Friday and we played Halo 3. Besides being the sensation that's sweeping the nation, Halo 3 is also filled with physics. I ran toward Nick (teh pretty pwny) as i shot him with my assault rifle. When i was near enough, i pressed B and beat him down. In Halo, beat downs are incredibly strong. You can shoot someone in the face with a machine gun for a long time and they won't die. However, if you hit them in the back with your gun, they will die instantly. Anyway, when i hit Nick with my gun his dead body flew across the map. I thought to myself, 'wow, with the mass of the gun being so small compared to the mass of his body, the gun must have been moving incredibly fast to fly Nick's massive body across the map'. Momentum conservation is fun!

Today i watched as my dog ran around in the yard. When i opened the door to let her in the house, she ran in and wanted to play. She was jumping around and barking, but i wanted to watch tv so i told her to go away. Then she turned around and ran straight into a chair. I have no idea why. Anyway, she was running really fast and she knocked over the chair. After i stopped laughing at her, i realized that if friction could be ignored, momentum would be conserved in this collision. The momentum of Kimi before the collision and the sum of momentums of the chair and Kimi after the collision would be equal.

This weekend the soccer team played a preseason game against Kalani. I was playing very poorly so coach benched me. As i sat on the bench and watched the game, i thought about physics and how i could turn soccer into yet another physics journal. When i got back into the game, it hit me. Literally. A ball bounced over my head and as i turned around to chase it, a Kalani forward hit me in the back. I fell forward and he landed on me. At first i was angry, but then i thought, "sticky collision!" When the kalani player hit me, i was standing still, facing the same direction as him. He had mass and velocity (and therefore momentum) which was transfered into me during the collision. After the collision, we both moved forward with the same velocity because he was on my back. Momentum is conserved in this (and every) collision, and this can be modeled in the equation: m1v1 + m2v2 = v(m1 + m2).

A small snowball starts on the top of a hill and rolls down, steadily gaining speed as well as picking up more snow. Eventually, the small snowball becomes a gigantic mass of snow moving incredibly fast. As i look back on the first quarter of physics, i find myself relating my experience to a snowball. When we started off the year i was a tiny snowball. I had no knowledge of physics or the windows it could open up in my life. However, as i began to roll down the 'hill' that is the first quarter of physics, i gained knowledge and efficiency (which is more snow and speed). Compared to the beginning of the quarter, i feel like i am a medium sized snowball moving at about 10 m/s. Although this is improvement from what i started out with, i hope to one day be a 1000 kg snowball moving at 100 m/s. I can achieve this by studying more thoroughly for exams and making sure i complete all labs competently. Overall, i am pleased with the first quarter of physics. :)

MASSIVE.

I was going to write another physics journal about soccer, but right now im watching South Park on Comedy Central and i've had an inspiration. This past week we learned about Newton's Laws of Motion, the first of which is the law of inertia. Inertia is an objects ability and tendency to resist change in velocity, and the more mass an object has, the more inertia. In tonight's episode, Starvin Marvin, a poor famished boy from Ethiopia, steals a space ship from an alien. He then flies the ship to America and picks up Stan, Kyle, Kenny, and Cartman. He asks them in his own language to help him stop the US CIA from moving all of his people to Australia. Anyway, as i was watching the space ship lift up the group of kids, i could not help but notice that the space ship must be working much harder to lift Cartman than to lift Starvin Marvin. Cartman is slightly overweight, and therefore has a lot of mass. This large amount of mass means that Cartman has a lot of inertia, and therefore a high resistance to change in velocity. This can be shown in the equation a=F/m. In order to keep the acceleration of the space ship, the force needs to be much higher in order to make up for the large mass in the denominator. This is different from Starvin Marvin, who has a very low mass. Subsequently, the space ship can exert a lesser force on Starvin Marvin and still have the same acceleration.

My little sister and her friends like to play with sprinklers in our front yard. Watching them playing with the water made me think about physics and what we learned this chapter. The sprinkler shoots water up into the air in eleven different streams, all pointed at different angles. The center stream of water shoots the water up the highest distance into the air, and thus the water from the center stream spends the longest time in the air. Although the other streams of water don't stay airborne as long as the center stream, all of the streams have the same Vo value. The streams other than the center have x velocity values, while the center does not. Not to mention, all the streams of water are projectiles and thus travel in a parabolic motion.

bouncing bowling ball

When an object is in a projectile motion, it generally looks like a parabola. As we learned this week, a projectile always has two elements: vertical movement and horizontal movement. Last night at our junior class bowling event, I watched as one of my classmates hurled the ball halfway across the lane and I thought to myself, "wow, that is a vector". Before the ball hits the lane, the ball has a parabolic motion. Its horizontal speed is constant while the vertical speed is lowest at the peak and speeds up closer to earth. After the ball hits the lane, however, it is no longer a projectile because it is not in the air. There is no longer any vertical movement because the ball is rolling on the ground. The horizontal speed is minimally affected because the grease on the lane reduces friction. This means that the ball will still have a lot of speed and erego a lot of momentum when it smashes into the pins.

My attitude toward physics so far is that it is a fun, hands-on learning experience. Although it is at times confusing, especially when involving correlating graphs, the satisfaction of gaining the knowledge in the end is instantly gratifying. Scalar values are always easier to deal with, and starting vectors adds to some of the confusion for me. Kinematic equations have been somewhat challenging, as i have never been great at memorizing equations and formulas. Discovering physics has made me feel like a huge smiley face because i am happy to be learning!

beach volleyball

This weekend i went to the beach with my family. As my cousins and I played voleyball on the sand, i noticed how the volleyball experiences change in velocity, acceleration, and displacement. When a volleyball is served, it goes through a negative acceleration as it moves up at a slowing pace, reaches its peak, and moves down across the net at increasing speed (9.8 m/s squared). This sequence of changes in acceleration and velocity in the ball continues until one team fails to return the ball, at which point the ball bounces, rolls, and slows to a zero velocity.