decorating a christmas tree

well, it's that time of year again! time for the tree to be decorated. time for presents. time for singing the birth of jesus. time for decorating a christmas tree!

so, for christmas, i helped decorate the tree (may i add that i only had the help from my mom and my little sister and no help from my brother and my dad). I must say, it is quite fun to decorate, but it also brings out physics principals!

For example, when picking up the ornaments, i am doing work. this is because i am moving an object in the direction of force that it is moving. score for physics! it's everywhere!

another physics example that i found while decorating the tree was that at the very top, i started to need the use of a stool of some sort to get to the very top. When i was bringing the ornaments to hand, potential energy was being added to that object because it was being moved to a greater height. also, i needed to make sure that my center of mass was being supported, otherwise i would fall while putting high ornaments on the christmas tree, and that would be very painful.

to think that christmas would bring out the spirit of physics!

box sliding

Although box sliding is a fun way to get hurt, it is also a fun way of learning about physics. Box sliding requires a hill with an angle. to slide as far as you can to get to the bottom of the hill takes skill and velocity. One must have a high initial velocity before landing on the cardboard to slide down the hill. unfortunately, in this picture, i had velocity but no skill on landing on the cardboard, so i totally wiped out.

also, the acceleration of gravity is the force that sends me downward. the only reason that i come to a stop is because friction makes me accelerate negatively, therefore making me slow down until i finally stop. the friction of grass on the cardboard is higher than friction of cardboard on cardboard, so therefore if i were to slide on cardboard, i would have slid down the hill longer than when i slid down on the grass.

that's enough pain for one day. :) peace.

chandelier

i was in my living room today, watching my brother play halo 3, when i noticed something about the chandelier that hangs in the living room. It is held by one ornate cord, which has tension because of the force of gravity exerted on the chandelier (which is mass times the acceleration of gravity). The tension in the cord-if it was assumed to have no mass-would have the same amount of force as the force of gravity to keep the chandelier at equilibrium and stay at rest. Unfortunately, in the real world, because everything has mass, the force of the tension in the rope and the force of gravity, although should be very close in number, are not exactly equal.

the great thing about the chandelier is that is also has the property of potential energy. If, for some bizarre reason, the tension in the cord that held the chandelier up broke, the force of gravity would force the chandelier to fall at a negative acceleration 9.8 meters per second. If we measured the height of the chandelier and the mass of the chandelier, we could easily obtain the velocity of the chandelier when it hit the ground because all potential energy would have been converted into kinetic energy (assuming that air resistance is irrelevant and no work is added into the system).

that's my physics epiphany for the day. ☺ see ya in a few weeks.

walking up stairs

Late tonight, my brother decided to walk up the stairs to my sister's room because he needed to give my sister a remote control for the television. When he picked up the remote control, he added energy to it (potential energy = mg x height). No work was done to the remote when he was walking around on a flat surface (work requires that there is force and a movement in the same direction as the force exerted on the object), but when he reached the stair case, work was exerted onto the remote control (because the vertical force he is exerting to keep the remote control in the air is now moving in a vertical motion).

One may wonder how my brother could be moving in a vertical motion even though my brother is not going straight upward. This is because his movement (which is diagonal) can be split into vectors. When splitting the movement into vectors, there are two components: a vertical force and a horizontal force. To find the magnitude of the vertical component, one would multiply the magnitude of the overall vector with the sine of the angle of the force.

How amazing it is that my brother walking up and down stairs can trigger Physics thoughts!

Learning Physics

Physics is one of the most interesting subjects I have ever learned. After the beginning of Physics, I started to think about the concepts of Physics in everything. When I run in a cross country race, I think, "Ack! Oh, man, everyone has a faster velocity than me!!!" When running down hills, the help of gravity makes me accelerate so that I can finish the race faster. At the end of the race, I'm happy that I've covered the distance of 3 miles, even though my displacement is less than 100 meters because the finish line is not that far away from the starting line.

Other than showing properties of Physics, Cross Country can also be an analogy of Physics in some ways. We start at the beginning of the course, prepared to work hard and do our best. Everyone goes at their own pace: some people understand Physics right away and excel; other people are slow to start and go at a steady pace. Even though everyone has different paces, everyone ends up at the same place at the end, learning the exact same things.

I may not be the fastest runner, and I might not be the fastest person to understand Physics. Fortunately, Everyone is on the same boat as me, learning at their own pace. I don't know if I can keep up with everybody, and I don't know if I will be able to excel as much as others excel in Physics, but I will keep trying my best and finish the race with as much effort as I possible can put into the subject. ☺

(by the way, this picture of me is from the Mid-Pacific Meet just yesterday. I got it from the pictures taken by Coach Al ☺)

Dropping Kirby

Today, I asked my sister Jodie to help me with physics. In this picture above, she's holding a stuffed Kirby (for those of you who do not know who Kirby is, It's a pink Nintendo hero that copies his opponent's foes special abilities, but that's irrelevant to physics).

While Kirby is being held in the air, it has inertia (since all objects have inertia). Inertia is the resistance of changing in its state of motion. For example, if an object is at rest, it stays at rest. On the other hand, if the object is in motion, it wants to stay in motion. Kirby is at rest, and it's acceleration is 0 meters per second squared. Also, Kirby's velocity is 0 meters per second.

Anyways, if Jodie were to drop Kirby, then Kirby would start to accelerate toward the ground because of gravity (which is -9.8 meters per second). Depending on how high my sister is, the velocity, when Kirby finally hits the ground, would be greater than 0 meters per second because of gravity. For example, if it takes two seconds for Kirby to fall to the ground, Kirby's final velocity, if you ignored air resistance, would be -19.6 meters per second (negative because it's moving downward motion).

In Physics, mass is known as the property of an object that determines how much it will resist a change in velocity. Kirby does not have much mass, so therefore Kirby will have more inertia than a larger, more massive object like an elephant. Because Kirby has such little mass, too, air resistance doesn't apply to it so much.

This is it for the Physics epiphanies today. ☺ I hoped you enjoyed Kirby and my little sister.

Stationary Bikes

When my mother was using her stationary bike today, it suddenly reminded me of a physics concept. As she keeps on cycling for any amount of time, her "distance" on the bike may say some funky number, like eleven miles, but she hasn't traveled anywhere. Even if she is exercising, her displacement will stay zero because she is not moving. Because her displacement is zero, her velocity will also be zero.

No matter how fast she pedals, no matter what her speed is, she will always stay at the displacement zero and her velocity will stay as zero. For example, the bike, which has a little screen that tells how far she has "traveled" and how long she has traveled, says that she has pedaled 1 mile in 10 minutes. Her average speed would be 6 miles an hour, but her displacement and velocity are both zero.

Sadly, my mother was hesitant to take a picture, and she hid her face with a newspaper while i snapped the photograph. With or without her face in the picture, she still perfectly demonstrates zero displacement and velocity.

Driving Physics Facts

Today, while I was dropping my friend off at her house, I saw a cop and it gave me a huge epiphany. This made me realize how much driving had to do with Physics.

When driving, people usually go a faster velocity than the speed limit (which is usually around 25 miles per hour around my neighborhood), but whenever they see a cop, they suddenly start to slow down to have the same velocity as the speed limit so that they do not have to worry about getting tickets. In the process of slowing down, the car goes through a negative acceleration.

Another physics fact about driving is that when you see a stop sign, you also have to slow down so that the velocity of the car will reach 0 mph, causing the car to go through negative acceleration.

That's enough Physics facts for today. By the way, I'm sorry about not having the picture of the cop, but I did not have a camera. ☺

(P.S. The cars in the picture are randomly taken close to my house.)