A big part of physics is the equations we use to solve for various aspects of concepts and ideas. I often feel as though the equations are nothing more than a series of numbers and letters that if I'm lucky enough to memorize, I can hopefully plug in some values here and there. However, in further explorations of accelerated forces today, I have a genuine understanding of the equations and the concepts they enforce.
F(net)=ma. Because acceleration is multiplied by mass to find force, these variable are inversely related! That means that as mass increases acceleration will decrease and vise versa! This concept was illustrated perfectly in the Air Track Lab we did. As we added more mass to the dragging object, the acceleration of the entire system decreased. But when we decreased the mass of the dragging object (and/or added mass to the falling object) the overall acceleration increased! This makes sense since the objects with more mass exert a greater fore of weight downward and objects with more weight have more inertia and are harder to move or accelerate!
Understanding that equation relates directly to the understanding of the following:
Total acceleration = weight of falling mass (m*g)/ total mass of all the objects
By dividing these variables you clearly illustrate their relationship. The equal sign between "total acceleration" and "weight of the falling mass" means that they are directly related and as the weight of the falling mass increases, total acceleration will increase.
Thursday, June 30, 2011
Wednesday, June 29, 2011
Unit 6 Post - 6/29: Forces with Acceleration
When you draw the Free Body Diagram of an object that is accelerating, not only is the object moving but it's changing speed (getting faster or slower) as it does! The forces acting upon the object aren't balanced which is why its velocity isn't constant.
In this video I illustrate a simple acceleration force by dragging my ipod across the floor, slowly at first, but then faster and faster to demonstrate how it changes speed. Obviously, my ipod represens the object. At first it's at rest - and at no time during the motion does it leave the ground; this means that two of the forces at work are the ipod pushing down with "weight" onto the Earth, and the Earth pushing up on the ipod with equal magnitude with "normal" force. The earphones inside the ipod are the force specifically pulling my ipod (obviously because I'm pulling it... but for the sake of the video, work with me here). The chord represents the unbalanced force of "pulling" to the left. The only force opposite this pulling is the friction of the floor, because it's rigid; however the pulling force is greater than the friction force thus leaving the equation unbalanced and the object to accelerate. Below is a more literal illustration of this motion.
In this video I illustrate a simple acceleration force by dragging my ipod across the floor, slowly at first, but then faster and faster to demonstrate how it changes speed. Obviously, my ipod represens the object. At first it's at rest - and at no time during the motion does it leave the ground; this means that two of the forces at work are the ipod pushing down with "weight" onto the Earth, and the Earth pushing up on the ipod with equal magnitude with "normal" force. The earphones inside the ipod are the force specifically pulling my ipod (obviously because I'm pulling it... but for the sake of the video, work with me here). The chord represents the unbalanced force of "pulling" to the left. The only force opposite this pulling is the friction of the floor, because it's rigid; however the pulling force is greater than the friction force thus leaving the equation unbalanced and the object to accelerate. Below is a more literal illustration of this motion.
Notice that the arrows of force in the up and down direction are equal magnitude, which is there is no acceleration in the y axis. However, the arrow for the pulling force arrow has much more magnitude than the smaller friction arrow in the opposite direction. It's not balanced, thus the acceleration on the x axis in the positive direction is justified.
Tuesday, June 28, 2011
Unit 5 Post - 6/28: Ukerub It Up!
Directions, magnitudes, and angles... OH MY! The "Ukerub" technique is all about thaking 2 vectors and getting one resulting one from which you can find the total displacement and angle of a "journey". First you define each of your given vectors in x and y terms (which may require the use of trigonometry functions), then add them together to find the resultant vectors in where you use opposite SOHCAHTOA to find the angle and Pythagorean Theorem to find your variables!
When learning about Newton's laws we learned about inertia and friction. Inertia is an objects ability to stay in the same state of movement that it's in. Friction is a type of force that works against motion and impending motion. In this video, I represent an object moving at a low and constant velocity with no acceleration. The only forces acting on me at that time are my weight downward and "normal" upward with equal force. My inertia is high because, although my velocity is low, I can maintain it easily. My friend Sam represents friction; with the support of the table, her mass is greater than my mass, so when come in contact I can no longer move. The force of her friction is greater than the force of the velocity I'm moving at or my force of inertia.
When learning about Newton's laws we learned about inertia and friction. Inertia is an objects ability to stay in the same state of movement that it's in. Friction is a type of force that works against motion and impending motion. In this video, I represent an object moving at a low and constant velocity with no acceleration. The only forces acting on me at that time are my weight downward and "normal" upward with equal force. My inertia is high because, although my velocity is low, I can maintain it easily. My friend Sam represents friction; with the support of the table, her mass is greater than my mass, so when come in contact I can no longer move. The force of her friction is greater than the force of the velocity I'm moving at or my force of inertia.
Monday, June 27, 2011
Unit 5 Post - 6/27: Newtons 3 Laws of Physics
Newton's three established laws of physics are some of the most fundamental and basis concepts of this science. His laws changed our understanding of the universe because they apply indefinitely to everything they refer to.
His first law states: "Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it."
This video shows a ball sitting still on a table. The ball is in motion, it has a speed and velocity of 0 m/s and no acceleration and has distance and displacement of 0m. This law says that the ball will continue to stay in this motion until something changes that! It's right! The ball just sits there, consistently sitting still. That is of course until I poked it. This was the "external force" that I applied to it in order to change its state of motion. When I poked it, the balls state of motion was changed!
His second law states: "The relationship between an object's mass (m), it's acceleration (a), and the applied force (F) is F=ma."
In this video, I used two balls to demonstrate Newton's second law. This mathematical formula is used to describe the force of objects in relation to each other. Both balls are dropped from the same height so they fall the same distance and are under the same acceleration of gravity (9.8 m/s^2) - in that respect they are the same. I take a moment in the beginning to show that the purple soccer ball is bigger than the tennis ball, it has a greater mass. This all means that when I run up the stairs to drop them, the purple soccer ball falls with more force than the tennis ball because it has a greater mass and the same acceleration!
His third law states: For every action there is an equal and opposite reaction."
This simple video accurately demonstrates Newton's final law. The action that occurs is me throwing the ball up at a certain velocity. The equal and opposite reaction is that the ball falls down (in the opposite direction) at the equal velocity I threw it up at for the same distance that it went up at! The reaction was both equal in distance and opposite in direction and both in velocity because when it came down it was going the same velocity but negative.
Source:
http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html
His first law states: "Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it."
This video shows a ball sitting still on a table. The ball is in motion, it has a speed and velocity of 0 m/s and no acceleration and has distance and displacement of 0m. This law says that the ball will continue to stay in this motion until something changes that! It's right! The ball just sits there, consistently sitting still. That is of course until I poked it. This was the "external force" that I applied to it in order to change its state of motion. When I poked it, the balls state of motion was changed!
His second law states: "The relationship between an object's mass (m), it's acceleration (a), and the applied force (F) is F=ma."
In this video, I used two balls to demonstrate Newton's second law. This mathematical formula is used to describe the force of objects in relation to each other. Both balls are dropped from the same height so they fall the same distance and are under the same acceleration of gravity (9.8 m/s^2) - in that respect they are the same. I take a moment in the beginning to show that the purple soccer ball is bigger than the tennis ball, it has a greater mass. This all means that when I run up the stairs to drop them, the purple soccer ball falls with more force than the tennis ball because it has a greater mass and the same acceleration!
His third law states: For every action there is an equal and opposite reaction."
This simple video accurately demonstrates Newton's final law. The action that occurs is me throwing the ball up at a certain velocity. The equal and opposite reaction is that the ball falls down (in the opposite direction) at the equal velocity I threw it up at for the same distance that it went up at! The reaction was both equal in distance and opposite in direction and both in velocity because when it came down it was going the same velocity but negative.
Source:
http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html
Friday, June 24, 2011
Unit 4 Post - 6/24: What Happens in Vegas...
You better shut your mouth... or I'll BUREKU your face! HAHAHA!!! Today I learned so much about solving physics equations that give you less information so you have to use more logic! Even though it was quite a challenge, it made me feel smart using such big numbers and complicated ideas. The "Bureku" technique is all about breaking vectors into equal parts so you can create variated right triangles based off of something like a single angle or velocity. When you form the right triangles you can use "SOHCAHTOA" (sine, cosine, and tangent trigonometry functions) to solve for legs of the right triangle you formed and give you velocities of the x and y axes. From there, the rest is history. I'm really enjoying discovering all the new ways to solve problems that I'd normally think were impossible.
An excellent application of this is the "Donkey Lab" that we did today in which we used our knowledge of physics to determine where a launched ball would land from scratch. This especially impacted me because using our knowledge of science and hard work, we created something real, tangible, and meaningful that went beyond just equations on paper. It was something that actually existed, actually mattered, I mean using that same science we could figure out where to drop a bomb or something (not the best example but... hey)! I was impressed and surprised not only that physics held such valid world application, but that we could really see how that application was real and we could make it happen on our own!
An excellent application of this is the "Donkey Lab" that we did today in which we used our knowledge of physics to determine where a launched ball would land from scratch. This especially impacted me because using our knowledge of science and hard work, we created something real, tangible, and meaningful that went beyond just equations on paper. It was something that actually existed, actually mattered, I mean using that same science we could figure out where to drop a bomb or something (not the best example but... hey)! I was impressed and surprised not only that physics held such valid world application, but that we could really see how that application was real and we could make it happen on our own!
Thursday, June 23, 2011
Unit 4 Post - 6/23: From X to Y; Accelerate All Over
Projectile motion takes the idea of acceleration one step further because it describes motion on both the x and y axes and their relationship with each other. One of my favorite things about this unit is the challenge of extracting information from word problems because it helps you to think critically and logically about the science behing what you're exploring. I really enjoy the challenge of combining the logic of the world and the scientific rules of science. This is one of those rare times in school where I value what I'm learning because it's not just pointless and insignificant to the reality of my life.
The following series of pictures is basically exactly what we did in learning about projectiles and movement on the x and y axis. In the first picture, the ball is traveling with no acceleration along the x axis only. In the second, the same is true, but as it approaches the drop gravity's acceleration begins to take ove. In the third picture, the ball is now traveling along the y axis as it falls accelerating at gravity's rate of 9.8 m/s^2 which means a new velocity as well! In the last picture, the ball is about to hit the ground and has long since finished traveling along the x axis and is about to finish traveling along the y axis. The ball took the same amount of time to go the distance of the x axis as it did the y axis; that's physics baby.
The following series of pictures is basically exactly what we did in learning about projectiles and movement on the x and y axis. In the first picture, the ball is traveling with no acceleration along the x axis only. In the second, the same is true, but as it approaches the drop gravity's acceleration begins to take ove. In the third picture, the ball is now traveling along the y axis as it falls accelerating at gravity's rate of 9.8 m/s^2 which means a new velocity as well! In the last picture, the ball is about to hit the ground and has long since finished traveling along the x axis and is about to finish traveling along the y axis. The ball took the same amount of time to go the distance of the x axis as it did the y axis; that's physics baby.
Wednesday, June 22, 2011
Summary of Physics Thus Far!
Acceleration is always the constant force of gravity : 10/ms^2 downward. However, velocity changes as something moves with or against gravity. If something goes upward, against gravity, at a specific velocity it will go up quick, go up slow (as gravity's acceleration takes over), stop briefly, come down slow, then come down quickly. The speed that the object goes up at is the same speed (oposite velocity) that it comes down at when it's at the same position coming down. I demonstrate this concept in the video below. The acceleration of my entire flipping journey is always 10 m/s^2 (because of gravity). Let's say that when I first take off and I'm 0.5 m above the ground I'm moving at 2.5 m/s velocity; when I come down and I'm about to land and I'm 0.5 m above the ground I'm moving at 2.5 m/s.
THROWBACK! In Unit 1 we learned about scientific notation and how it's used to express especially large or small numbers in a more convenient way so you can manage them effectively. You move the decimal point to make the base number between 1 and 10, and how ever many places you moved the decimal place is the exponent above the 10! If the decimal point made a small number a big number, the exponent is negative, if it made a big number a small one the exponent is positive. This reminded me of how we use coins or paper money to express specific amounts of money to make them more manageable. I took the picture below to demonstrate how scientific notation works with the more applicable example of money: 10 pennies, 5 nickels, 4 dimes, and 1 quarter vs. a simple dollar bill.
In conclusion, in learning about physics I really learn about the world around me. When you look beyond the formula's and the confusing concepts, the science behing physics is truly the science of our world.
Tuesday, June 21, 2011
Unit 3 Post - 6/21: Acceleration (Continued)
I took this video on the car ride home with my mom, it was late so at times its hard to see some of the detail. The video demonstrates many of the different concepts regarding velocity. In the beginning we increase our velocity and accelerate to a faster speed. Then we maintain that speed, so even though we were going 75 mph (hahaha) we had no acceleration. A car pulled in front of us and our exit approached, which meant it was time to slow down. This meant that we experienced negative acceleration, and a lower velocity. Then we came to a complete stop, not only did we have no acceleration (because we were maintaining our speed of 0 mph) but we had no velocity as well. It was a lot of fun!
Today, one of the biggest accomplishments in my understanding of physics and acceleration was units! Units are everything! Even if you don't completely understand the problem, you have a good chance of making something work if you just keep your units in tact. Understanding that acceleration is measured in m/s^2, time is measured in seconds, and distance in m will get you pretty far if you know what you're doing. The second thing was understanding the differences between each type of graph and discovering ways to use the information it gives you efficiently. For example in a speed vs. time graph, if you want to find distance, you don't have to do some complicated formula - just find the area of the region below the curve of the specified section.
Today, one of the biggest accomplishments in my understanding of physics and acceleration was units! Units are everything! Even if you don't completely understand the problem, you have a good chance of making something work if you just keep your units in tact. Understanding that acceleration is measured in m/s^2, time is measured in seconds, and distance in m will get you pretty far if you know what you're doing. The second thing was understanding the differences between each type of graph and discovering ways to use the information it gives you efficiently. For example in a speed vs. time graph, if you want to find distance, you don't have to do some complicated formula - just find the area of the region below the curve of the specified section.
Monday, June 20, 2011
Unit 3 Post - 6/20: Acceleration
Acceleration is defined as a change in velocity per unit of time measured in m/s^2. Basically it means a change in the rate of speed. Acceleration doesn't have as much to do with the specifics of position; it does however describe total displacement and defines positive acceleration as moving away from the origin while negative acceleration is moving towards the origin.
This video is a simple recording of the fishes in my aquarium. Fishes seldom are still, they're always moving. Often they aren't moving towards a specific destination - they're just moving! This reminds me of acceleration! Acceleration, like I said, usually describes displacement opposed to destination. Fish don't move towards a destination, but they don't visit the same spot twice - so they have a lot of displacement which you can see in my video. Also, I tapped the glass during the video to scare them and make them swim faster to demonstrate a change in speed. If you watch the fish, you see how they move slowly sometimes, then speed up, then slow down, and so on! A great practical application of acceleration!
Friday, June 17, 2011
Unit 2 Post - 6/17: Origins, Destinations, and the Journey
Today it all made sense! We continued studying motion, but this time around the big words and the subtle differences weren't quite as scary. With just a little bit of mental work and some real world logic you can understand the difference between velocity vs. time graphs and distance vs. time graphs and how what they show you relates to each other. When we applied what we were learning to word problem stories, a clearer picture was painted in my head of what we were studying. That application was the turning point in helping me understand kinematics. So, as you can see below, I decided to make my own.
This picture describes my mom's journey to her room in a velocity vs. time graph which has a slope that describes acceleration. She decided she was on her way, but before she could go I got a little hungry and asked her to get me a snack from the kitchen. She reluctantly agreed and slowly walked at a constant rate the kitchen, giving me that "mom glare" the entire way, because meant she was walking in the opposite direction of her destination from where she came from. She got the the kitchen and quickly stayed there while putting together something yummy for me! The line is short because she didn't stay there long and has no velocity (positive or negative) because she wasn't moving. When she was finished, she decided to hurry up to her room. The line is of positive velocity because she's moving away from her origin to her destination and its further away from the base line because she's moving at a faster velocity. The line is longer because her room is very far away so it took a longer time to get there.
This graph describes my journey from my bed the car in the morning when I'm on my way to summer school in a distance vs. time graph. The difference between this graph is that it's slope describes velocity and it's consistency; also this graph demonstrates position as well! I wake up and roll out of bed; tired and groggy I half sleep-walk to the bathroom to get dressed and ready. The bathroom may be close to my room but the line has a shallow slope because I'm walking so slow, and the line is long because it takes so much time to get there. Once I finally manage to trudge to the bathroom, I stay in there a little bit to get ready. Brush my teeth, change clothes, all of the things it takes to be as fabulous as me. However, halfway through I realize how tired I am and how painful this is. The line is flat because I'm staying in one place with no velocity; but the line is short because I don't stay in there for long. Like I said, I'm not a morning person, and I can get ready in 5 minutes flat, so I decide that it's back to bed with me! With all the energy I have, I dash back to the comfort of my pillows and blankets to wait out the sunrise. This line has a steeper slope because I'm moving at a higher velocity, but it has a negative slope because I'm moving back to my starting point.
Thursday, June 16, 2011
Unit 2 Post - 6/16: In the Fast Lane With No Direction
Physics is really forcing me to look at my world in a different way, and I love it! The subtle, yet imperative differences between distance and displacement or speed and velocity are direct applications to my world! Critical thinking is a big part of our educational growth, and now when I go running on a track versus running a trail, I have a deeper understanding of that! When I'm fast-walking to class because I'm late, but then stop for five minutes to talk to a friend, I can understand the science behind that!
It's hard to point to one specific thing and say that it was the most important aspect from unit 2. All of it was new to me, all of it was important to me, all of it taught me something new that allowed me to see things in a different light! The two pictures (... one of which that INVOLVES MY PARENTS ; ) above present the variety of topics we learned about. We were all headed to Tommy Bahama's at Waikele for some Father's Day Shopping. I decided to take my bike (not actually MY bike for the record) while my parents drove in order to represent speed and velocity. The van can go much faster than me, therefore it has a greater speed and therefore a greater velocity (it's slope on a line graph would be steeper). However, we are headed to same destination so we were moving in the same direction and traveled (about) the same distance. After we went shopping, we returned home; back where we started. Thus, even though we moved at different speeds and velocities, we traveled the same distance and had a displacement of zero. Funny how this stuff seems so confusing in the classroom but truly comes alive in our day to day.
It's hard to point to one specific thing and say that it was the most important aspect from unit 2. All of it was new to me, all of it was important to me, all of it taught me something new that allowed me to see things in a different light! The two pictures (... one of which that INVOLVES MY PARENTS ; ) above present the variety of topics we learned about. We were all headed to Tommy Bahama's at Waikele for some Father's Day Shopping. I decided to take my bike (not actually MY bike for the record) while my parents drove in order to represent speed and velocity. The van can go much faster than me, therefore it has a greater speed and therefore a greater velocity (it's slope on a line graph would be steeper). However, we are headed to same destination so we were moving in the same direction and traveled (about) the same distance. After we went shopping, we returned home; back where we started. Thus, even though we moved at different speeds and velocities, we traveled the same distance and had a displacement of zero. Funny how this stuff seems so confusing in the classroom but truly comes alive in our day to day.
Wednesday, June 15, 2011
Unit 1 Post - 6/15: Mass Don't Matter!
In unit 1 we discovered the foundation of physics and learned ways to describe and present various concepts and ideas with regards to this science. Scientific notation, dimensional analysis, and describing the relationship between variables in both graphs and equations are namely some of the things we explored.
One of the biggest things that impacted me was the pendulum experiment because it was hands on, active, and fun! Having a huge string swing thing hanging in the classroom was definitely the right way to get us motivated on the first day. Beyond that, the experiment really taught me something and genuinely surprised me! When discussing the different quantitative measurements and observations we could explore, I hypothesized that the mass of the weight on the pendulum would have a direct relationship with the period.
I chose the two pictures below because they properly illustrate this idea. If you saw an elephant on a swing, you might thing that it would swing for a much longer time than a hamster on a swing under the same circumstances of being released at the same angle and being on a pendulum of equal length. But the reality is, it would have little to no effect on the period at all! Although the masses are different, mass and weight are two different things, and mass has no affect on gravitational acceleration - which is based on weight. The links below are the sources of the pictures.
One of the biggest things that impacted me was the pendulum experiment because it was hands on, active, and fun! Having a huge string swing thing hanging in the classroom was definitely the right way to get us motivated on the first day. Beyond that, the experiment really taught me something and genuinely surprised me! When discussing the different quantitative measurements and observations we could explore, I hypothesized that the mass of the weight on the pendulum would have a direct relationship with the period.
I chose the two pictures below because they properly illustrate this idea. If you saw an elephant on a swing, you might thing that it would swing for a much longer time than a hamster on a swing under the same circumstances of being released at the same angle and being on a pendulum of equal length. But the reality is, it would have little to no effect on the period at all! Although the masses are different, mass and weight are two different things, and mass has no affect on gravitational acceleration - which is based on weight. The links below are the sources of the pictures.
Tuesday, June 14, 2011
Information About Me: 6/14
Hey! My name is Joshua Smith, I'm 16 years old and I'm a rising Junior at Punahou whose been here for 2 years. I love meeting new people and experiencing new things in hopes that I'll take away all that life has to offer while giving back to the people and the beauty that has inspired and offered me so much.
Science has always been a subject I enjoyed because it explains the mysteries of this world in a tangible way. So far I've taken Biology Honors, Chemistry, and plan on taking a Psychology course in the upcoming year.
Math isn't something that comes easy to me, but my work ethic always get me through. So far I've taken Algebra 1, Geometry, and plan on taking Algebra 2/Trigonometry in the upcoming year.
From this class I hope to learn a lot about physics, and it's application to the world around me. I look forward to being surprised to seeing just how prevalent physics is in my life specifically. By immersing myself in a fast paced intensive course, I also hope to improve my work ethic and study habits for all of my educational career as well.
(Pictures in magazines, movie screens)
Vanity
(There is a camera, so many beauty queens)
Vanity
(It's so good to be)
Fabulous and glamorous, we love ourselves and no one else
Nothin' wrong with being just a little bit vain
We need a little pretty 'cause this country's insane
So go ahead and label me whatever you like
But nothings quite as sexy as a woman is fine
Science has always been a subject I enjoyed because it explains the mysteries of this world in a tangible way. So far I've taken Biology Honors, Chemistry, and plan on taking a Psychology course in the upcoming year.
Math isn't something that comes easy to me, but my work ethic always get me through. So far I've taken Algebra 1, Geometry, and plan on taking Algebra 2/Trigonometry in the upcoming year.
From this class I hope to learn a lot about physics, and it's application to the world around me. I look forward to being surprised to seeing just how prevalent physics is in my life specifically. By immersing myself in a fast paced intensive course, I also hope to improve my work ethic and study habits for all of my educational career as well.
The story behind this picture is pretty simple, I had a photo-shoot with a friend of mine because I wanted to and it made me happy. The importance of the art of glamour, vanity, and narcissism is a tragedy that I willingly suffer. Don't think too hard about it. It's may not be justified, possibly unverified, but it's my way of life - for me there is no other. In the words of Mother Monster, Lady Gaga:
Vanity(Pictures in magazines, movie screens)
Vanity
(There is a camera, so many beauty queens)
Vanity
(It's so good to be)
Fabulous and glamorous, we love ourselves and no one else
Nothin' wrong with being just a little bit vain
We need a little pretty 'cause this country's insane
So go ahead and label me whatever you like
But nothings quite as sexy as a woman is fine
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