What I've learned from Physics...

I've learned many things from Physics...However, I'd prefer not to name every single little fact...

We covered 2D Kinematics first in which we learned about mass, acceleration, velocity, time, distance, scalar and vector quantities, magnitude, gravity, and some conceptual things. For example, if an item is tossed up with a velocity of 10 m/s, at the top of its flight, the object has a velocity of 0 m/s and at the bottom it has -10m/s. Gravity on earth is ALWAYS 9.8 m/s^2--what changes in the object's flight path is velocity, not acceleration. 

Next we learned about triangles and axes. (Axes are independent by the way; what happens on the x-axis stays on the x-axis. Same for the y-axis.) This helped when we covered later units--the Break Technique does exactly what it sounds like; it breaks the diagonal up into two separate horizontal and vertical parts.

Then we covered forces and Newton's laws. The first one states that objects at motion will tend to stay in motion unless acted on by an outside, unbalanced force. Replace "in motion" with "at rest" to get the other half of the law. The first law is also known as the Law of Inertia. The second law states that acceleration of an object is directly proportional to the net force on an object and inversely proportional to the mass of the object. The third law says that for every action/force, there is an equal and opposite action/force. We also learned about Normal Force, tension, terminal velocity, frictional force, and pulleys.

Next we covered Momentum. The law of conservation states that momentum can neither be created nor destroyed; it just changes forms. Impulse is the change in momentum. And like force, the impulse experienced by two objects pushing against each other is the same.

Lastly, we covered energy, which is entirely confusing. Energy also can be neither created nor destroyed; it only changes forms. Work is not power. Power is the rate at which work is done. 

(We did not cover linear momentum...or Keplar's Laws...or some other things on the review packet...so I hope they are not on the test even though they're in the review packet...)

The picture is because after this semester is over, I can visit my uncles in LA.

エネルギ

Energy is measured in joules, which is kgm^2/s^2, or Nm. It is a scalar quantity, which means that it only has "muchness." Work is Force * Displacement; it is different from power, which is the rate at which you do work. The equation for power is Work / Time. Therefore Time is irrelevant to Work, but very much relevant to Power. Do not mistake the two. 

IfI raced my friend who weighs the same as me to Nijo Temple in the back of the photo, and she finished 2 seconds before I did, we would have done the same amount of work. However, because she finished before me, she'd be using more power than me.

Here are some equations we've learned for work...

Potential Energy (s) = 1/2kd^2

Potential Energy (g) = mgh

Kinetic Energy = 1/2mv^2

It seems relatively easy so far...But when you toss in drawings of springs, ramps, friction, and wind tunnels, everything starts to get a bit more confusing.