Force Field!!!! O.o

A couple of weeks ago...or a...few days ago actually, we learned about light emitting rays that are not visible to the human eye, but have a glow. We also learned that they have the capability to extend this invisible force on forever, pointing in all directions. The strength of the glow depends on many factors such as the light's voltage, etc. But the important thing is to know that light is not limited, but extends on forever, getting dimmer and dimmer the farther it goes. That's why when Mr. Kohara activated the lighter, we could see a glow not in the flame but around it. It hurt to look, but hey, I learned something out of it! This glow is not only seen in light bulbs, like the picture, but signs as well, pretty much anything that emits light! You can see this on an airplane when traveling in the night, the city lights glimmering or when you eat at a restaurant and you see the glowing OPEN sign. Its all around us. FORCE FIELDS! OOOOH

Can't Touch This!

Nowadays as technology increases, our dependency seems to be straying away from gas and moving towards batteries, electronics, and outlets. Yet the idea of electric seems to correlate with voltage. While Electrical forces equals F= kQq/r^2, and fields equals E = f/q = kQ/r^2, voltage is another animal. Voltage is a ratio of potential energy over the charge. so one volt is equivalent to 1 joule of energy over 1 coulomb. Though sometimes you can see voltage as a huge number, it can be harmless depending on the ratio. A Coulomb itself is large, but for example, the Van De Graff generator pumps out 400,000 volts yet contains only a fraction of a Coulomb. (Hence it is why i am still alive today). Remember, just like speed, voltage is a ratio, which it is not necessarily the number you see. But if the Van De Graff generator DID have 1 Coulomb, I'm sorry to say, but you wouldn't see me here today. In this picture, I am showing a wall outlet, as an example of something with great voltage, enough to kill you, make you faint, or paralyze you. Can't touch that!

Torque and Moment of Intertia!

Here we can see torque in another great perspective. The equation for torque as we know is T=rf. R being the distance from axis to force, and f representing force. But another way we can look at the door handle is as I, moment of inertia. According to 11.6, a door handle like this one (solid cylinder with axis running along the center) is represented by I= .5MR^2. This amazing equation only requires you to know the radius and the mass. Once you have that, we have a masterpiece! By the way, just for reference, moment of inertia is "the measure of resistance to angular acceleration."

During This Short Break...

After getting bored out of my mind, and realizing that a physics journal is due this break, I decided to read a bit about Archimedes and his principal on water. According to Kinetic Books, he states that: An object in a fluid experiences an upward force equal to the weight of the fluid it displaces. To show that, i got a rubber duck i found somewhere in my closet from an Axe gift set long ago. I placed the duck in a bucket and experienced what he meant. The book continues on to explain about The upward buoyant force which allows an object to float if less than the buoyant force. If greater, it would sink like a dense rock. This is why a gigantic piece of Styrofoam can float. "Its less dense than water and displaces a weight of water equal to its own weight. It is in a state of equilibrium and floats." The same principal works with the way fish live. They have something called a swim bladder, in which when it expands, becomes more buoyant, and when deflates, becomes less. This allows them to float when buoyant, and sink when not.

The Magical Wrench

Today in class, we learned a new type of force, one that is rotational called torque. Torque is force in a rotational direction and has an equation of: t = rf, where t is the torque, r is the distance from the axis to the force, and f is the force. A wrench is a perfect example, as you use your hands to turn the bolt to release or tighten, creating torque. And when using a wrench, the farther out you place your grip, the easier it is to turn, since r is increased creating more torque to open up the bolt. This is why some construction workers use extra tubes to connect to the small tools to make their life easier. Though they may not know how it exactly helps, we do! Definition of torque according to Kinetic Books: A force that causes or opposes rotation!

Sound Waves

While pondering about what to write for this journal, I was listening to I Miss You by Blink 182, and realized that my sound system could actually be my journal this time for physics! After reading about it in chapter 17.1, I realized sound waves have a lot to do with physics. Apparently, my sound system produces sound waves, which according to my text book are "longitudinal mechanical waves in a medium like air generated by vibrations such as the plucking of a guitar string or the oscillations of a loudspeaker." What sound waves do is create compression in the air, which then soars and makes it possible to hear. Compression literally compresses the air in front of the speaker's diaphragm, and sends out this compression into the air. These particles from the waves consistently move "forward and backward" according to the book, as the diaphragm constantly decreases pressure by moving inwards, causing a process called rarefaction. Therefore, your sound system creates a cycle like path where it is constantly moving in and out, compressing and rarefaction, and back to compressing! :) Note: The sound system connected to my laptop consists of the three white domes!

Potential Energy??? HECK YEA!

As I was pondering about what to do for my next physics journal, I thought of the easiest one ever. POTENTIAL ENERGY! Potential Energy is simply once something is above ground, it has a stored energy called potential energy. The equation for this is PE = mass x gravity x height. So here in my picture, I am standing right outside my balcony into the distance, knowing that I have Potential Energy! Even when walking around the house and jumping up and down, I have potential energy AND Kinetic energy in respect to the ground floor. But in respect to the carpet at home, I have NO potential energy whatsoever, unless i somehow climb on top of a chair or table. Kinetic Energy is basically when an object is in motion. The equation for this is KE = .5 x mass x velocity^2. Cool, isn't it? Note: In a frictionless condition, the following equation applies, when transitioning between potential and kinetic energy: PEa + KEa = PEb + KEb!!!!