Work, Power, and Force
This week in Physics, we learned about work, power, and force.
Work is equal to any change in energy.  It can be found by the equation  W = f (force) • d (distance), and is measured in Joules (J).
Work is related to power because power is the rate at which work is being done.  Power = work / time and is measured in Watts (W).
We also learned about energy.  In an isolated system, energy can not be created nor destroyed, it just changes form.  There are two forms of energy; potential (energy of position) PEg = mass • height • gravity, and kinetic (energy of motion) KE = 1/2 mass • velocity^2.

Below we have a dog.  This dog does work while playing fetch because it exerts a certain force for a certain distance on the stick being used.
PC: Noʻe

I'm Thankful For....
I'm thankful for Physics because it helps me understand why things work in the way they do.  I am thankful for Blake and Freitas because they make learning fun and enjoyable.  They make me look forward to coming to another crazy class.  In physics, I'm thankful for gravity (an unbalanced outside force that acts on objects at -9.8m/s^2 in the y-axis).  It allows us to live our lives on earth the way we do.  It also prevents us from floating off into space.  I'm also thankful for acceleration, momentum, and mass because it allows us to perform daily tasks that are necessary for us to live.  I am thankful for Newton because he explained why things happen the way they do in his 3 laws.   Physics shapes life on earth as we know it.

Momentum and Impact
This week in Physics, we learned about momentum and impact.  The Law of Conservation of momentum states that in an isolated system momentum will be conserved.  Momentum is measured in kg • m/s and can be found using the formula P=m • v (P=momentum, m=mass, and v=velocity).  In the picture below, the momentum of the wave carries the surfer along its face.  This momentum transfers to the surfer allowing him to move with the wave.  This momentum can be manipulated by the surfer allowing him to perform maneuvers.  Momentum in = momentum out.

We also learned about impact.  Shorter impact time = greater impulse.  Longer impact time = less impulse.  In the water balloon toss activity the balloon broke when it hit the ground because of its short impact time.  When the sheet caught the balloon it did not break because it increased its impact time.

Forces That Accelerate
This week, we learned more about Newton's Laws of motion.  More specifically, acceleration and Newton's second law.  Newton's second law states, 'the acceleration of an object is directly proportional to a net force on an object and the acceleration of an object is inversely proportional to the object's mass.  From this law, we learn that acceleration is directly proportional to the Fnet (sum of all forces), and that acceleration goes down as the mass of an object goes up (vice versa).  This is represented by the equation a=Fnet/mass.
Fnet can be found by the equation Fnet=m•a.  (m = mass, a = acceleration)

A force that accelerates is a skater.  While cruising around my neighborhood, I noticed that I was accelerating with every push I took. I realized that as i pushed on the ground, the ground pushed me back and accelerated me forward.

And Fight Club was a very good movie.

Newton's First Law
This week in Physics, we learned about Newton's laws.  His first law titled, "Law of Inertia", states that objects in motion (or at rest) will tend to stay in motion (or at rest) unless acted upon by an outside, unbalanced force.  For example, a ball at rest wants to stay at rest and only moves when it is kicked or thrown.  In this case, the outside, unbalanced force is the person kicking or throwing the ball.

This bunch of bananas are a perfect example of Newton's first law.  They are at rest therefore they want to stay at rest.  The only way they would move is if they were moved by an outside, unbalanced force which would be someone grabbing them.

Projectiles (Part II)
A projectile is any object moving through the air where the only force acting upon it is gravity.  As the projectile is thrown into the air at its given initial velocity, it accelerates at a rate of -9.8m/s^2 in the y-direction.  Meaning it moves in a fast-slow-stop-slow-fast motion pattern.  However, on the x-axis it moves at a constant speed.  This unique combination causes the projectile to move in a parabolic motion.
During physics this week, we practiced finding unknown values dealing with projectiles.  Initial velocity, range of the y and x axis, and time of flight were just a few we were able to find.  Physics also allowed us to predict the landing of a silver ball given its velocity, height, and acceleration.

The picture of the skater below is a projectile.  His motion in the x-axis is constant whereas he is accelerating at -9.8m/s^2 in the y-axis.

Relative Motion (Pt. 2)
All motion is relative, but relative to what?
Motion is different for everyone and everything in all situations.  For example, take an airplane.  relative to the pilot and passengers, the plane is not moving.  But, relative to the buildings and people on the ground, the plane moves at 500 mph.  Relative to planes flying in the opposite direction, the plane could appear to be flying close to 1,000 mph.

In this hilarious photo of my friend, Mario, he displays relative motion without breaking himself in the shore break at Sandy's.  Relative to the board he was using, he is not moving.  This is because he is moving at the same speed as the board.  Relative to the people on the beach, he is moving toward them because the force of the wave has pushed him closer to the shore.  Relative to the shallow sandy bottom, he is moving closer (at a rate of 9.8 m/s).

Projectiles
This week in Physics, we learned about projectiles.  Any object upon which the only force is gravity is considered a projectile.  Projectiles may be represented by a parabolic graph because they have a constant speed on the x-axis, but a changing speed in the y-axis (fast-slow-stop-slow-fast).  In a projectile, the x-axis usually remains at a constant velocity while the y-axis velocity slows down then increases again because of gravity's affect.  This is known as 2-D kinematics.

The picture below features a construction-worker having re-living his childhood memories or perhaps blowing off some steam from a frustrating day of work at the Hawaii Kai skatepark.  He is not considered a projectile yet because his wheels are still on the ground.  But, as soon as he airs the bowl, he will become a projectile and move on the x-axis with a constant speed, and the only force affecting him will be gravity.

Vectors
This week in Physics, we learned about Vectors.  Vectors are quantities that deal with both direction and magnitude (amount).  During a lab we did during class, we were able to conclude that an example of everyday vectors is football plays.  As the receivers make runs and cuts, they act as vectors.  We also learned how to add vectors.  Vectors may be added by connecting the tail of one vector, to the tip of the other.  A "Resultant" vector is the answer or the measurement from the tail of the first vector to the tip of the last vector.  The picture below is a fireworks show in Waikiki.  I believe its an example of a vector because it shoots up in to the sky then bursts into numerous embers.  Its resultant can be measured from where it is shot all the way to where its fire runs out.

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PC: Mario K.

End of 1st Quarter

As the first quarter of school goes by, I realized that I've already learned so much about Physics.  We have been focusing mainly on motion, also known as "Kinematics".  We've also learned a lot about velocity and acceleration.  The Graph Matching and Ball Toss labs have really helped to better our understandings on the material being covered during class.  I think i’ve already learned a bunch of new things that I can apply to my everyday life.  This class is helping me to understand why things happen and how they relate to Physics.  So far, I am enjoying this class and the knowledge it provides for me.  The photo below was taken by me and is of my friend Chance.  It illustrates kinematics.

Introduction

My name is Adjin K.M. Watson.  I entered Kamehameha Schools in 9th grade, and i'm from Hawaii Kai.  My interests include playing soccer, surfing, skating, and hanging out with my friends.  So far, I've completed BSCS Biology with Mrs. Forster and Chems Chemistry with Kuba.  Currently, I am taking College Algebra with ma boy Mr. Del Prado.  As a result of completing Physics, I hope to gain a better understanding of why things around me happen.  I believe that almost everything going on in this world has some connection to Physics.  The photo below is a picture of me skating at the Hawaii Kai skatepark.  PC goes out to my friend Carter.  This photo represents me not only because I am featured in it, but because it shows that I enjoy having a good time.

Acceleration

This week in physics, we learned more about kinematics.  More specifically, we covered the topic of acceleration.  Acceleration is represented by the slope of a Velocity vs. Time graph and can be found by the equation a = ∆ v / ∆ t.  Acceleration is usually measured in meters per seconds squared (m/s^2).  The most practical example of acceleration is a car.  The accelerator or gas pedal is pushed to accelerate the car.  The car accelerates at different rates depending on how hard the accelerator is pushed.  If the car accelerates at a constant rate, the graph will be linear.  However, the graph will differ if the car is not accelerating at a constant rate.  The photo below shows a captured image of the trail of light left behind when a car accelerates.  The more acceleration the car has, the more blurred the light trial will be.

Acceleration and Velocity
This week in physics, we learned more about Kinematics and motion.  We touched more upon acceleration and velocity.   Velocity, measured in meters per seconds squared (m/s^2), is found by taking the slope of a position vs. time graph.  Acceleration, measured in meters per second (m/s), is found by taking the slope of a velocity vs. time graph.  The picture below represents both acceleration and velocity because as the skater pushes off the ground he increases his acceleration.  When he coasts down a hill or maintains a certain speed while skating the streets, his velocity is constant.  When doing speed checks (as shown below) a skater is able to manipulate his velocity.  Physics never fails to explain everyday occurrences.

Position vs. Time

In this picture, we see a local skater doing an air out of a bowl.  Whats appealing to the eye has a
greater meaning.  With a "Physics Mentality" we see position vs time.  As the skater drops into the bowl, he accelerates down the ramp to generate speed.  As time goes on, he maintains this speed in order to air off the other side of the ramp.  Displacement is also a factor in this case.  If the skater decides not to do an air, he would turn around and go up the initial ramp he went down.  When the skater returns to his starting point, he displaces the area he covered going down the ramp.

Kinematics:
Kinematics is the study of motion.  From common knowledge, it is easy to say that anything and everything can either move on its own or be manipulated to move.

One thing that is not so commonly known is that "all motion is RELATIVE".  The first question that comes to mind is "relative to what?'

Above is an example of motion.  Not only is there a surfer moving along the face of the wave, but the white water behind him is also moving.  The surfer is moving relative to the wave as he carves up and down and relative to the people in the water and on shore.

The wave is moving as well.  When a surfer goes straight across the face of the wave it seems like the wave is not moving because they are both traveling at the same speed.  Relative to the surfer, the wave is not moving.  But, it is easily seen from shore and in the water that the wave is in fact moving.  Therefore, relative to the other surfers and spectators on shore, the wave is moving.

As the wave brings the surfer closer to shore, the surfer sees the shore approaching him.  We all know that the shore isn't actually moving itself closer to the shore, but it appears this way.  The shore is moving closer relative to the surfer just as the line-up is moving further away relative to the surfer.

This example justifies that all motion in relative.

Accuracy vs. Precision

What appears to be a messy laundry basket holds a greater hidden meaning.  This is my basket of laundry.  Clothes hang from the sides, fall short, and lay in the small space between the basket and the closet door.  But what does this have to do with Physics?  

Everyday, my basket serves as a "hoop" as I "drain" free throws from my dresser.  Unfortunately, I don't have the best free throw average.  The bulk of my clothes are behind my basket.  Some make it around the sides and fall short, and even fewer actually make it into the basket.  

My poor shooting make for the perfect science lesson on Accuracy vs Precision.  Its obvious that I have poor accuracy.  This is because I hit the desired target less 20% of the time and shamefully have to pick up my clothes whenever guests come over.  Accuracy is how close you are to getting the result you want to, which I clearly failed to do.  But, I have high precision because for about 70% of the time I hit the little space between the back of my basket and the closet door behind it.  Precision is getting the same value multiple times.  In this case, its overshooting and making it into the space behind the basket.

A Physics lesson can be made of the most practical things.