The Phsyics of Kicks

This past weekend, as I was wasting time before going to work, I was looking at all of my pictures from this school year. I came upon the pictures above are of Erika, Gavin, Jon, Jon, and Me when we went out to the soccer field to kick around the ball. I had no idea we had to do a physics journal this weekend until Erika told me so, and before I knew this I was actually looking at the pictures of us kicking the ball with a physics eye! I recalled in class when Mr. Kohara attempted to demonstrate how a system's angular momentum is "zero" as long as there is no outside torque acting on it. The demonstration was slightly convincing, as he threw a football and told us to watch his feet, and even made Grant and Gavin do it to prove that he wasn't just exaggerating it for the sake of physics. Although I could see what he meant I never fully believed it until I came upon our pictures and realized how when we kicked the ball, our arms went in the opposite direction. Even when Gavin was heading the ball in the last picture, his left leg sticks out behind him. I'm not sure if that's an example of angular momentum being "zero," but it seems like it! Or, at least, he's trying to balance his forward movement of his upper body with the lifting of his leg, thus being an example of center of mass and how different positions change where the center of mass is, causing Gavin to feel the need to use his left leg to compensate his header. I just realized why we would need to keep our angular momentum at "zero" (I never realized it before), because if we didn't we would keep on going in the direction we were spinning! Like momentum, once you get some angular momentum, you tend to keep it. Without our upper body spinning the opposite way, we would keep on spinning in the same direction after the kick! Wow I finally get why helicopters need both rotors! Thanks, Physics! :)

ChristMas Tree CM

Today my dad, my mom, and I carried up our 8-9 foot noble fir chrismtas tree from my garage up the stairs and into my living room. When we got there after much struggling on my dad's part, and relatively little on mine, we had to put the christmas tree into its stand. Our first concern was that the trunk of the huge tree wouldn't fit into the stand, however, that fear was quickly abated when it fit fine, however, soon after we discovered that making the tree stand straight up and keeping it there would be our real problem. After many"1-2-3 lift"s in efforts to screw the tree in straight, we came to the conclusion that the tree was too topheavy to stand on its own. In the second picture you might be able to see how we kept the tree up, by tying a fishing wire from the tree's trunk to a nearby window shutter. That solution worked, as the tree is still standing now. But why did we have to resort to this barbaric form of tree standing? Because the tree's center of mass must have been out of the range of the tree stand's support area. If the tree's CM had been within the support area of the stand we would not have had to use the fishing wire. Now that the tree is up, the next problem is how to decorate that wire to make it less obvious. Any suggestions?

Paddle Paddle Paddle!

The day we took this picture Erika and I had paddling and we came back to school and Justin and Gavin were there. They took our paddles and tried to practice their strokes while sitting on the table. I never really thought of it at the time, but the reason why they didn't go anywhere, even with Gavin's big muscles and Justin's expert steering skills, was because the forces pushing back on the paddles weren't great enough to overcome the weight of the table. If they had been in the water they would have gone really far because of the water pushing back against the paddle, and because of the way the canoe is built and because of its weight. This is Newton's Third Law, for every action there's an equal and opposite reaction. The weight of the table makes the forces applied by the paddles almost negligible.

WORK iT

Shucks. All the pictures uploaded backwards. Anyway. Today Erika, Justin, and I worked on our physics journals at my house and on my hill. We focused mainly on work and potential and kinetic energy. I chose work because I wanted to set up my punching bag. As you can see in the bottom picture, Justin is struggling to hold up the 100 lb punching bag by himself. Even though he's having a LOT of trouble holding it up, he's not doing any work. Why not? Because work requires force and motion in the direction of the force. Because Justin is holding the punching bag in place, he's not changing the position at all, although he's getting tired, he's doing no work. In the second, third, and fourth pictures, Justin and I are raising the punching bag to hang it up onto the chains. We are doing work in these pictures because we are lifting the punching bag, therefore applying force and displacing the punching bag, changing its position. When we actually started punching the bag, we were using energy, another new concept we learned. When Justin and I punched the bag, the energy put into the punch did not simply disappear, it was absorbed by the punching bag and turned into a different form of energy. The law of conservation of energy states that energy is neither created nor destroyed. I'm not quite sure where the energy went, but because we're in physics I can confidently say that it must still exist!

Physics Pheelings

I think that I actually expected physics to be quite hard, and I was right. I heard it was going to be fun, but like all of my science classes it has been challenging. I'm not doing as well as I'd like to right now, not by far, however, I know that it's because of my procrastination and lack of asking for extra help. I know that if I have better time management next quarter and actually make the time to get help, then I'll get it. These pictures show how I am before extra help, then how I am after. Like a monkey/gorilla/whatever that is scratching its head to a light bulb that gets it!

An anxiety I have is not being able to simulate the problems in class on a quiz or test, which always happens. However, this anxiety could be appeased easily by just going to extra help or studying more. A reservation I have is that I can't do any labs by myself, I always need help, but I actually think that that's the point of labs, that you're supposed to exchange ideas and learn from them. If we knew all of the answers to a lab without having to discuss the questions then there wouldn't be any sense in doing them.

Again, I think I could be doing way better if I put in more effort and actually asked for help when I needed it, which is pretty much all the time. I'm pretty much looking forward to a fresh start next quarter and I hope I take my own advice and go in for extra help because I need it!

Cookie Time!

So taking these pictures took many tries, with a ton of flashes and about two dog treats, but with my dad's help we got them! Because it took so much effort I'm putting four pictures up. Anyway, after playing catch with my dog, Cookie, a dalmation labrador, for how more than 7 years now I finally see that it's actually related to physics! The bright yellow tennis ball is not only an example of a projectile, as when it leaves my dad's hands its path is only affected by the force of gravity, but it is also a great example of inertia! Inertia is Newton's first law, stating that an object remains at rest, or maintains a constant velocity, unless a net external force acts upon it. If not for the force of gravity, the tennis ball would travel toward the ground at a constant velocity, however, it accelerates down to earth at -9.8 m/s^2. The ball also would have proceeded at a constant velocity toward the ground if not for Cookie catching it in her mouth. Cookie acts as another net external force that interrupts the object, in this case the tennis ball, maintaining a constant velocity. If we were playing fetch/catch in space, with no gravity, Cookie would still act as the net external force and interrupt the tennis ball's tendency to maintain a constant velocity.

I wonder if there's any physics in the different colors that are in Cookie's eyes in the 1st, 2nd, and 3rd pictures...Maybe I'll explore that next time! =)

Water Fountain Fun

Last weekend, when I was getting a drink of water during a break in a meeting, I noticed that the more I pushed on the water fountain button/lever/whatever it's called that the water would shoot up higher. I'm sure that all of us have done this at one point in time, shooting water up our friends' noses when they asked us to hold the lever down for them. Back then, this was just a silly prank, but now that I'm in physics I can see that this is actually the work of velocity and gravity! The higher the velocity that the water is shot out of the fountain (the more push that is applied to the lever), the higher the water will shoot out (the higher the peak of its motion), and vice versa. The arc that's formed from the flow of water is due to the pull of gravity, the negative acceleration of all objects on earth (-9.8 m/s^2). At the peak of the three pictured arcs, the velocity of the flow of the water is 0 m/s because it's changing from positive to negative, however, it's still accelerating since its velocity is changing.
All objects thrown/catapulted/hurled/launched/etc. into the air without anything like a parachute or jet pack helping them to stay up will form arcs like those pictured above. Even professional atheletes who appear as though they're floating in the air when they jump are affected by the pull of gravity, accelerating back down to earth at -9.8 m/s^2.