As I was studying for my Physics final I realized that there was a toy I got from my parents as they have always given me "educational toys." This one I found showed me how circuits work in an extremely simple format. Using the snap circuits you can easily construct parallel, complex, and series circuits. I got this toy, and who knew it could help me so much? A simple child inspiring toy, applied toward the qualitative understanding of physics.
Here is their link: http://www.elenco.com/
Monday, May 24, 2010
Wednesday, May 19, 2010
Connections Through Circuits! Shocking!
SERIES CIRCUIT- In the diagram above we see a series of identical resistors on a wire in a closed loop. The current through the wire is constant, but the voltage is variant upon the resistors in which it travels. The voltage found across both resistors is equal to one half of the voltage across just one resistor because the resistors are identical and the voltage must be provided for both light bulbs. The equivalent resistance we can find in the circuit is equal to the sum of the values of resistance in Ohms added to each other. Therefore we can conclude that the current is constant across the entire wire as there is not a paralell circuit.
PARALELL CIRCUIT- In the image above we see a paralell circuit. In this circuit there are two equivalent resistors that can be treated with an equivalent resistance acting upon the current of the entire wire. The equivalent resistance can be found by adding the inverses of resistances. Inside the paralell circuit the voltage is constant, but the current varies. We can look at voltage as the capacity to do work.
COMPLEX CIRCUIT- In this complex circuit we have a battery, a switch, and then a series of resistors, two in paralell, and one in a series. The voltage flows from the battery without resistance that sends a current through the wire that feeds the light bulb with electricity. The voltage across the wire adds up to the voltage provided by the battery, but is variant upon the resistance. Voltage "pressure" makes the electrons move, and this "pressure" depends on the resistance in which it travels through, similarly to knotting a hose. The current is constant on the wire outside of the paralell circuit, but inside the paralell circuit the current is reduced because it must feed upon the two light bulbs (resistances) in the paralell. The paralell circuit has an equivalent resistance, and therefore we can treat it as an individual resistor for total current, and voltage. The current through each resistor is not then same, but the current sum inside the paralell circuit is the same as the current that goes through the lone resistor on the wire.
A DC (direct current) is the flow of charge that does not vary in direction. Direct current is used in batteries, solar panels, and when electricity is transported large distances across a wire. This require a closed loop, a switch, and resistors across the wire. In a direct circuit there is a direct flow of voltage.
Sunday, May 2, 2010
Optics Reflection
In our most recent unit, geometric optics, I learned quite a lot about how light travels and interacts with mirrors, lenses, and various mediums. We began our units by learning about waves and sound. Through this unit we were introduced to the most basic topics that were necessary to understand color, light travel, refraction, diffraction, and reflection. This unit introduced us to frequency, speed, wavelength, and the Doppler effect. In this unit we also used online wave simulations that demonstrated interference, whether it be constructive, or destructive. After this briefing, we began to talk about mirrors. We had various labs where were experimented with flat mirrors, concave (converging) mirrors and convex (diverging) mirrors. In these experiments we were proved the relation between the focal point and the radius of curvature. After these qualitative experiments, we were introduced to a style of determining the qualities of images formed by mirrors called the ray-tracing method. We proceeded to learn about the focal point, radius, center of curvature, real images, virtual images, upright images, and inverted images. This style of ray tracing has three standard light rays (1, 2, and 3) that go from a fixed position on the reflected object to the mirror in a certain fashion as follows: ray 1 is drawn parallel to the normal line, and is then reflected off into the focal point; ray two is draw through the focal point, and then reflected off of the mirror parallel to the normal line; ray 3 is drawn from the figure to the center of curvature. As we draw these ray-tracing models we write down the characteristics of the images formed. After mastering these concepts we learned the quantitative application to optics. We discussed and determined how to conclude image characteristics based on our numbers we solved for. After this we learned about Snell's Law of image refraction. We then moved on into lenses and talked about the uses of lenses for people with poor vision and how glasses work. This was particularly fascinating when Cyrus, one of my classmates who is a very fascinated and driven by studies in the brain, gave a presentation from his blog on how the eye works. We learned about diverging and converging lenses, and learned how to do ray-tracing diagrams for these as well. We learned that the characteristics of the images lenses produce are very different from how we call the characteristics of images formed by mirrors. This was a very informative unit full with information and plenty more to study, discover, and explore in the future.
In this unit we covered a lot of material in a very timely manner and I found lenses very difficult. I thought that I had understood mirrors very well, but when we began studying lenses I was fascinated, but a little bit overwhelmed by the differences. I found converting quantitative numbers in problems difficult to turn into characteristics and apply them.
-Eric
Sunday, April 25, 2010
Parabolic Beauty
In Parabolic Beauty, we can see the parabolic motion of water from a garden hose. The pressure which drives the water through the hose and causes the initial water velocity and is derived from a water reservoir elevated above the level of the hose. The gravitational attraction of the water to the earth is based on the mass of the water and the earth. The potential energy is converted into kinetic energy when the water flows downward through the pipe system to the hose nozzle. The velocity of water in the horizontal direction is constant. In contrast, the gravitational force of the earth, constantly accelerates the vertical component of the water’s motion. At the apex the water's vertical motion is zero. Likewise, when the water reaches the level of the hose the vertical component of velocity is equal to the vertical component of velocity when it left the hose, except that the vector is in the opposite direction. In addition, the beautiful red color of the roses and the verdant green foliage are examples of natural pigment reflection. In the case of the roses, the pigment that makes the roses red absorbs other colors of light, and reflects the red wavelengths of visible light causing them to appear red.
Friday, March 26, 2010
Einstein Quote (Response to the Responses)
In my personal opinion, as of now, I think that school is a great place to be introduced to accepted knowledge, and touch on topics that are required in the curriculum. In my formal education I have been exposed to many new topics and concepts that are very important to further learning and discovery, as well as everyday life. Through my classes I have learned very much about English, Science, Spanish, History, and Math, but much of this learning, in my opinion, has involved a lot of pure memorization, "busy work," and strict methods of problem solving. In fact, Einstein had the same accusation of modern education.
Similarly to Einstein, I think that all of the "busy work," and memorization has been done only to do well on the assessments, but it has not actually helped me in any other sector. Einstein was a master of solving problems, and I think that problem solving is a skill that does not come naturally. In my learning in math over the years, the problems introduced to us have merely been execution and routine. I commonly find myself doing the same problems with different variations. Although this is very important, I do not believe that this should be the responsibility of the teacher. I think that in school teachers should introduce a topic and be accessible for assistance, and extra challenges to improve our problem solving skills. I am forced to ask myself, "In modern education is it possible to educate the entire youth population without forcing students to do "work"?" "What is the responsibility of the curriculum for advanced and deeper studies?" "Is deeper knowledge the responsibility of the student?"
In education, you get from your classes from what challenges you take upon yourself. Students have the opportunity to take honors and AP classes, excel in the class, and complete the work thoroughly. In one of my previous reflections I mentioned that one of my goals as a student has been to not only complete the assigned work, but also fully grasp the topic. This takes a great amount of discipline as I also have great amounts of other work to complete, and as the hours of work become greater. To a certain extent I think that the school system has forced the student to learn knowledge that the student is not interested in, and this causes for behavior issues that disrupt the rest of the class from advancing in our studies, and cause students to lose focus and determination in school. At the same time teachers give students such a burden of brainless busy work that when the teacher has them in class the student has trouble focusing, and get behind in the class.
The reason why schools teach students this style of learning in order to succeed in academics is very valid. If there is not work imposed on the students they conclude that the student will not learn independently. As a society, the majority of the youth population would not choose to sit through certain classes, or have the desire to grasp topics. As a nation we value the importance of education for many reasons. Having an educated population helps our economy, makes our nation more productive, keeps crime and poverty to a minimum, and also provides opportunity to be successful.
One idea that I have had is what would happen if we let students study in certain fields of study more heavily? To be honest I am more excited to learn in certain classes. One conversation my study hall had involved three categories. First being the information we know, second being the information we do not know, and thirdly the information we know that we do not know. This conversation we had recently caused me to be more appreciative of the classes where I am not so thrilled about learning. We had a discussion about broadening the category of the things that we know we do not know. We discussed how the smaller this is "the more scary of a person we are." Although in whatever field of study we pursue we may not ever need some of our imposed knowledge, it makes us less ignorant of other studies that we now know we do not know.
In conclusion, I believe that the school system does a fairly good job of educating. The current solution to these problems is by offering these advanced courses for the student who is excited to take on challenges, and deepen their knowledge.
Similarly to Einstein, I think that all of the "busy work," and memorization has been done only to do well on the assessments, but it has not actually helped me in any other sector. Einstein was a master of solving problems, and I think that problem solving is a skill that does not come naturally. In my learning in math over the years, the problems introduced to us have merely been execution and routine. I commonly find myself doing the same problems with different variations. Although this is very important, I do not believe that this should be the responsibility of the teacher. I think that in school teachers should introduce a topic and be accessible for assistance, and extra challenges to improve our problem solving skills. I am forced to ask myself, "In modern education is it possible to educate the entire youth population without forcing students to do "work"?" "What is the responsibility of the curriculum for advanced and deeper studies?" "Is deeper knowledge the responsibility of the student?"
In education, you get from your classes from what challenges you take upon yourself. Students have the opportunity to take honors and AP classes, excel in the class, and complete the work thoroughly. In one of my previous reflections I mentioned that one of my goals as a student has been to not only complete the assigned work, but also fully grasp the topic. This takes a great amount of discipline as I also have great amounts of other work to complete, and as the hours of work become greater. To a certain extent I think that the school system has forced the student to learn knowledge that the student is not interested in, and this causes for behavior issues that disrupt the rest of the class from advancing in our studies, and cause students to lose focus and determination in school. At the same time teachers give students such a burden of brainless busy work that when the teacher has them in class the student has trouble focusing, and get behind in the class.
The reason why schools teach students this style of learning in order to succeed in academics is very valid. If there is not work imposed on the students they conclude that the student will not learn independently. As a society, the majority of the youth population would not choose to sit through certain classes, or have the desire to grasp topics. As a nation we value the importance of education for many reasons. Having an educated population helps our economy, makes our nation more productive, keeps crime and poverty to a minimum, and also provides opportunity to be successful.
One idea that I have had is what would happen if we let students study in certain fields of study more heavily? To be honest I am more excited to learn in certain classes. One conversation my study hall had involved three categories. First being the information we know, second being the information we do not know, and thirdly the information we know that we do not know. This conversation we had recently caused me to be more appreciative of the classes where I am not so thrilled about learning. We had a discussion about broadening the category of the things that we know we do not know. We discussed how the smaller this is "the more scary of a person we are." Although in whatever field of study we pursue we may not ever need some of our imposed knowledge, it makes us less ignorant of other studies that we now know we do not know.
In conclusion, I believe that the school system does a fairly good job of educating. The current solution to these problems is by offering these advanced courses for the student who is excited to take on challenges, and deepen their knowledge.
Sunday, March 21, 2010
Einstein Quote
"The only thing that interferes with my learning is my education."
After studying Einstein in my younger years I have learned that Albert Einstein was a trouble maker in school and commonly did not do his work using methods that were taught, or he did not do the work at all. In fact Einstein thought that organized education was rather silly as it narrowed his ability to explore more areas of learning. Einstein was a very bright kid and proved his genius later on in his life through studies in science, theology, and physics. Einstein was never shy to take on challenges and to think out complicated thoughts and problems. In fact he once said "It's not that I'm so smart , it's just that I stay with problems longer ." I think that in Einstein's rare case school was not an opportunity to become very complex in thinking, but to learn more about the things that he knew that he didn't know that made him less ignorant and more driven to explore. Obviously Einstein was frustrated with formal education and thought that it was a mere waste of his effort, but I do believe that school introduced him to concepts for that which he was able to deepen his studies and explore independently.
After studying Einstein in my younger years I have learned that Albert Einstein was a trouble maker in school and commonly did not do his work using methods that were taught, or he did not do the work at all. In fact Einstein thought that organized education was rather silly as it narrowed his ability to explore more areas of learning. Einstein was a very bright kid and proved his genius later on in his life through studies in science, theology, and physics. Einstein was never shy to take on challenges and to think out complicated thoughts and problems. In fact he once said "It's not that I'm so smart , it's just that I stay with problems longer ." I think that in Einstein's rare case school was not an opportunity to become very complex in thinking, but to learn more about the things that he knew that he didn't know that made him less ignorant and more driven to explore. Obviously Einstein was frustrated with formal education and thought that it was a mere waste of his effort, but I do believe that school introduced him to concepts for that which he was able to deepen his studies and explore independently.
Thursday, March 11, 2010
Group 6: Ski Jumping
For Group 6's project we used a glogster and a pixton to explain our topic of Ski Jumping in the winter Olympics. Enjoy!!
Below is a Pixton. It is a digital tool used to help to create online comic strips. Our group used it to explain how physics relates to Ski Jumping as well as the winners for the 2010 winter Olympics.
Below is a glogster, which is a digital took which helps to create an online collage, being used to explain and introduce ski jumping as a sport (including rules, equipment, and even two video)
Ski Jumping Glogster
Attributions:
1. (ski jumping images) Flickrstrom author: johnny9s
2. (ski jumping videos) Youtube
3. (information) www.abc-of-skiing.com, www.wikipedia.org,and
www.canada.com/sports
Below is a Pixton. It is a digital tool used to help to create online comic strips. Our group used it to explain how physics relates to Ski Jumping as well as the winners for the 2010 winter Olympics.
Below is a glogster, which is a digital took which helps to create an online collage, being used to explain and introduce ski jumping as a sport (including rules, equipment, and even two video)
Ski Jumping Glogster
Attributions:
1. (ski jumping images) Flickrstrom author: johnny9s
2. (ski jumping videos) Youtube
3. (information) www.abc-of-skiing.com, www.wikipedia.org,and
www.canada.com/sports
Sunday, February 21, 2010
The Conservation of Energy!
Part A:
This is what I learned about the Conservation of Energy. When we were first introduced to energy we asked, "What is energy?" Well to be honest I found that question very hard to answer. I sat in my seat and thought about electricity, springs, elastics, fuel, and my favorite, food. I asked, "What do all of these things have in common?" Well we later learned that energy is the potential to "do work." For example: By lifting weights the energy I use from my food intake is used to lift the weight and therefore give it potential energy due to its height in relation to a reference point that can be the ground, or where the weight started. The energy I put on the weight did not disappear, in fact, energy never disappears in our universe. The energy actually it is transferred into another form, this being kinetic (motion), elastic (spring or stretching related), potential (in relation to a specific height), or internal (as in various forms of friction that can lead to heat). Energy can be stored in different forms, but it can never disappear. Although by the end of my work out I am very tired and energy depleted, the energy I have lost has actually only been transported to other forms around me. This concept is useful while we solve problems that are asking about energy. We can set up equations to find the quantity of various forms of energy at different periods of time in Joules (Newtons x meters). This quantity represents "work" which can be found by finding the product of Force (N) and distance (m). The work that is done happens over a period of time, which gives us a rate of work accomplished, which is known as power. The unit of power is Nm/time (Watts - W). What I really enjoy about energy is that the quantitative value of energy is constant throughout the situation. When we began we made energy charts where we were required to identify the system and show where all of the energy dissipated. After grasping this concept options of problems we can solve become infinite with the simple concept that the original energy will be present in the final result. Since Joules is a universal unit it can be easily tracked throughout the problem.
Originally when we began studying the concept of the conservation of energy I had a hard time interpreting and drawing qualitative graphs of energy problems. Part of my problem was that I did not originally understand what each form of energy really was. Through out the "clicker quiz," the class work, and our Physics Quest, I was especially able to grasp the concepts through contemplation. The process was not easy and that Physics Quest took much more time than it would take me now, but now I go into problems with a more open mind and consider any possible transfer of energy. Our Physics Quest had several difficult problems that cause me to create a checklist of different forms of energy. This technique has helped me tremendously, and I would recommend it to all of you! If you go down the line of different forms of energy in your head, it will be much easier to understand the problem, and you will make far fewer mistakes.
My problem-solving skills have continued to improve. I have been more "snappy" toward understanding how to set equations equal to each other and have items cancel out. This has been especially important in this unit because we have the constant variable that is the energy that never leaves the system. This forces us to work while setting the original energies equal to find the current states of energy. Once I understood the qualitative concepts of energy, the quantitative was very natural.
Part B:
An example of how our energy knowledge is applied to our everyday life can be found while watching many of the winter sports on TV. A great example of this was while Shaun White, an American half pipe expert, completed his two runs. The start of the half pipe is uphill which gives him potential energy due to gravity, his mass, and height. Shaun White left the start and proceeded down hill, gaining Kinetic energy. As he changed elevations during his jumps his Kinetic energy and potential energy changed, but the sum of the energy remained constant. His board made friction with the snow and left Internal energy. We know that the total energy of the system was constant throughout each of his runs, although it was constantly changing states.
Wednesday, February 3, 2010
FINAL PROJECT
How can we apply physics to a
bike that is making a turn on a flat track verus a banked track?
I appreciate all comments! Thanks to all who helped make this release better! I took your comments into consideration and made significant changes to my project.
Notice that at one moment in time the friction is static! Therefore we can use static "MU's."
Tuesday, February 2, 2010
Eric's Physics Project over Bikes
How can we apply physics to a
bike that is making a turn on a flat track verus a banked track?
I appreciate all comments! Thanks to all who helped make this release better! I took your comments into consideration and made significant changes to my project.
Notice that at one moment in time the friction is static! Therefore we can use static "MU's."
Monday, February 1, 2010
Attributions
http://www.icteachers.co.uk/children/sats/images/gravity.gif
http://d3f8w3yx9w99q2.cloudfront.net/1268/hampton-fitness-55-100-lbs-dura-bell-dumbbells-set-dumbbells/hampton-fitness-55-100-lbs-dura-bell-dumbbells-set-dumbbells_0_0.jpg
http://www.diverse-group.com/page1/files/mac-os-x10-5-leopard_1.jpg
http://images.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/4/4c/Studded_tires.jpg&imgrefurl=http://commons.wikimedia.org/wiki/File:Studded_tires.jpg&usg=__HgDh3PyCaosNhcwVLF7jdK0GsVM=&h=1268&w=1312&sz=306&hl=en&start=16&um=1&tbnid=Hyz8Y3bksEQk7M:&tbnh=145&tbnw=150&prev=/images%3Fq%3Dbike%2Btires%26hl%3Den%26client%3Dsafari%26rls%3Den%26um%3D1
http://en.wikipedia.org/wiki/Friction
http://motoaus.com/images/stories/ducati2008/xaus-hypermotard.jpg
http://3.bp.blogspot.com/_g3_LbRMsQYc/SxGnHNy7gyI/AAAAAAAAEa0/qG1E63d8tO8/s1600/400px-Greek_lc_mu.svg.png
http://images.askmen.com/blogs/sports/lance-armstrong-the-best-ever.jpg
http://www.physicsclassroom.com/Class/Newtlaws/u2l2c1.gif
http://www.bikeradar.com/gear/article/lance-armstrongs-trek-madone-69-livestrong-20045
http://www.examiner.com/x-14380-NY-Celebrity-Fitness-and-Health-Examiner~y2009m7d20-Lance-Armstrong-vs-Alberto-Contador-Is-body-weight-a-factor
http://www.google.com/search?client=safari&rls=en&q=165+lbs+to+kg&ie=UTF-8&oe=UTF-8
http://blog.newsok.com/gossip/files/2009/02/lance-armstrong.jpg
http://img2.timeinc.net/people/i/2004/04/weekinphotos/040802/larmstrong.jpg
http://www.youtube.com/watch?v=Bg1ymKYuWak
http://tell.fll.purdue.edu/JapanProj/FLClipart/Adjectives/fast.gif
http://upload.wikimedia.org/wikipedia/commons/9/97/Centripetal_force.PNG
http://scrapetv.com/News/News%20Pages/Business/images-2/Billy-Mays-pointing.jpg
http://www.trekbikes.com/us/en/bikes/road/madone/madone69/
http://www.bookshelfboyfriend.com/uploaded_images/fullsize/301bike-wheel-diagram.jpg
http://zenwerx.com/pi.png
http://cdn.mos.bikeradar.com/images/news/2009/01/21/1232542708618-n89r7gk8ypak-850-65.jpg
http://www.driversedguru.com/wp-content/gallery/auto-accessories/tire-pressure-valve-caps.jpg
http://faithfulfiend.files.wordpress.com/2009/03/lance-armstrong-kaws-trek-road-bike.jpg
http://prezi.com/yqfewccn5th-/edit/#58
http://weblogs.cltv.com/news/weather/traffic/armstrong-contador_1440595c.jpg
http://road.bike198.com/wp-content/uploads/2009/12/lance-armstrong.jpg
http://nimg.sulekha.com/sports/thumbnailfull/lance-armstrong-2009-8-15-14-43-20.jpg
http://www.singletracks.com/blog/wp-content/uploads/2008/11/lance-armstrong.jpg
http://dunningrb.files.wordpress.com/2009/01/cycling_tour_de_france_tdf1075z7.jpg
http://d3f8w3yx9w99q2.cloudfront.net/1268/hampton-fitness-55-100-lbs-dura-bell-dumbbells-set-dumbbells/hampton-fitness-55-100-lbs-dura-bell-dumbbells-set-dumbbells_0_0.jpg
http://www.diverse-group.com/page1/files/mac-os-x10-5-leopard_1.jpg
http://images.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/4/4c/Studded_tires.jpg&imgrefurl=http://commons.wikimedia.org/wiki/File:Studded_tires.jpg&usg=__HgDh3PyCaosNhcwVLF7jdK0GsVM=&h=1268&w=1312&sz=306&hl=en&start=16&um=1&tbnid=Hyz8Y3bksEQk7M:&tbnh=145&tbnw=150&prev=/images%3Fq%3Dbike%2Btires%26hl%3Den%26client%3Dsafari%26rls%3Den%26um%3D1
http://en.wikipedia.org/wiki/Friction
http://motoaus.com/images/stories/ducati2008/xaus-hypermotard.jpg
http://3.bp.blogspot.com/_g3_LbRMsQYc/SxGnHNy7gyI/AAAAAAAAEa0/qG1E63d8tO8/s1600/400px-Greek_lc_mu.svg.png
http://images.askmen.com/blogs/sports/lance-armstrong-the-best-ever.jpg
http://www.physicsclassroom.com/Class/Newtlaws/u2l2c1.gif
http://www.bikeradar.com/gear/article/lance-armstrongs-trek-madone-69-livestrong-20045
http://www.examiner.com/x-14380-NY-Celebrity-Fitness-and-Health-Examiner~y2009m7d20-Lance-Armstrong-vs-Alberto-Contador-Is-body-weight-a-factor
http://www.google.com/search?client=safari&rls=en&q=165+lbs+to+kg&ie=UTF-8&oe=UTF-8
http://blog.newsok.com/gossip/files/2009/02/lance-armstrong.jpg
http://img2.timeinc.net/people/i/2004/04/weekinphotos/040802/larmstrong.jpg
http://www.youtube.com/watch?v=Bg1ymKYuWak
http://tell.fll.purdue.edu/JapanProj/FLClipart/Adjectives/fast.gif
http://upload.wikimedia.org/wikipedia/commons/9/97/Centripetal_force.PNG
http://scrapetv.com/News/News%20Pages/Business/images-2/Billy-Mays-pointing.jpg
http://www.trekbikes.com/us/en/bikes/road/madone/madone69/
http://www.bookshelfboyfriend.com/uploaded_images/fullsize/301bike-wheel-diagram.jpg
http://zenwerx.com/pi.png
http://cdn.mos.bikeradar.com/images/news/2009/01/21/1232542708618-n89r7gk8ypak-850-65.jpg
http://www.driversedguru.com/wp-content/gallery/auto-accessories/tire-pressure-valve-caps.jpg
http://faithfulfiend.files.wordpress.com/2009/03/lance-armstrong-kaws-trek-road-bike.jpg
http://prezi.com/yqfewccn5th-/edit/#58
http://weblogs.cltv.com/news/weather/traffic/armstrong-contador_1440595c.jpg
http://road.bike198.com/wp-content/uploads/2009/12/lance-armstrong.jpg
http://nimg.sulekha.com/sports/thumbnailfull/lance-armstrong-2009-8-15-14-43-20.jpg
http://www.singletracks.com/blog/wp-content/uploads/2008/11/lance-armstrong.jpg
http://dunningrb.files.wordpress.com/2009/01/cycling_tour_de_france_tdf1075z7.jpg
Wednesday, January 27, 2010
Circular Motion and Gravitation Reflection
This is what I learned about Circular Motion. Objects in circular motion have a constant velocity, or "Uniform Circular Motion." In these cases the objects are experiencing an inward or centripetal acceleration. Although the velocity's magnitude does not change it is accelerating because it is changing direction. The objects velocity at any given point is tangential. You can find a tangential line by drawing a line through the circle that only intercepts the circumference in the exact point of the object's location. The objects in circular motion move along the circumference or perimeter of the circle. The perimeter of a circle can be calculated by 2 pi R or pi D. The frequency is the number of full circular rotations per unit of time (s), also known as Hz, and the Period (T) is the time for the object to complete one entire rotation around the circle. In order to keep an object in a circular motion there must be an inward force. This is also known as the "centripetal force requirement.” Commonly this force is friction, found by multiplying Mu and Fn, the x component of tension, or gravity. The minimum force needed to keep an object in circular motion can be found by using the equation Fc=mv^2/r giving you units (N). You can find the centripetal acceleration by using the equation Ac=v^2/r giving you the units (m/s^2). In vertical circular motion the tension in the string or cable varies with the position of the object. At the highest point and lowest point in a circle you find the centripetal force that must equal (mv^2/r). This can easily be found by drawing an FBD with an arrow showing the object's acceleration. Any force working with the acceleration is positive and any force moving in the opposite direction of the acceleration is negative. Just as in problems involving torque, and systems you put the forces moving in the direction of the movement or acceleration as positive, and the forces moving in the opposite direction of the acceleration as negative.
This is what I learned about Universal Gravitation. Isaac Newton proposed an abstract theory that all masses attract each other, just as the earth attracts all objects in and outside of its atmosphere. He proposed "Every object in the universe attracts every other object in the universe (FG) with a force(G) that varies directly with the product of their masses(m1 and m2) and inversely with the square of the distance between the centers of the two masses(r^2)." This gives us the primitive equation Fg=Gm1m2/r^2 that can be manipulated to solve for any item in the equation. The "G" in the equation has been calculated by Cavendish as 6.67e-11 (N.m^2/kg^2).
What I have found difficult about what I have studied is setting up equations where you have masses and variables that "cancel out." This is something that some people have an eye for, but I am learning to recognize these occurrences in common circumstances. I have learned what the source of gravity is, and how planets, satellites, and moons are in a constant state of "freefall." I think that by learning circular movement I now better understand frictional force.
My problem-solving skills have become better in recent weeks. Some problems in our homework assignments and recent flying pig and "Holy Cow" labs have really made me realize the power of physics. I have tested myself by thinking about problems constantly as I go through my normal daily routine. While going through my day I sometimes think back to the problem that puzzled me earlier. By helping other students with problems and asking for help on assignments I think that our class community has done a good job helping each other grasp concepts. I think that I could take advantage of our wiki more and get feedback from more than just the one friend I call, and at the same time, help the entire class better learn or be exposed to a concept in a new way.
This is what I learned about Universal Gravitation. Isaac Newton proposed an abstract theory that all masses attract each other, just as the earth attracts all objects in and outside of its atmosphere. He proposed "Every object in the universe attracts every other object in the universe (FG) with a force(G) that varies directly with the product of their masses(m1 and m2) and inversely with the square of the distance between the centers of the two masses(r^2)." This gives us the primitive equation Fg=Gm1m2/r^2 that can be manipulated to solve for any item in the equation. The "G" in the equation has been calculated by Cavendish as 6.67e-11 (N.m^2/kg^2).
What I have found difficult about what I have studied is setting up equations where you have masses and variables that "cancel out." This is something that some people have an eye for, but I am learning to recognize these occurrences in common circumstances. I have learned what the source of gravity is, and how planets, satellites, and moons are in a constant state of "freefall." I think that by learning circular movement I now better understand frictional force.
My problem-solving skills have become better in recent weeks. Some problems in our homework assignments and recent flying pig and "Holy Cow" labs have really made me realize the power of physics. I have tested myself by thinking about problems constantly as I go through my normal daily routine. While going through my day I sometimes think back to the problem that puzzled me earlier. By helping other students with problems and asking for help on assignments I think that our class community has done a good job helping each other grasp concepts. I think that I could take advantage of our wiki more and get feedback from more than just the one friend I call, and at the same time, help the entire class better learn or be exposed to a concept in a new way.
Sunday, January 10, 2010
Reflection 2
This is what I learned about Newton's Second Law. Newton's second law is Net Force equals mass times acceleration. In order to use our given information you must analyze the exact meaning of it. You must know in which direction the object is moving. Once you now this fact, you decide which forces are helping the object move in that direction and which ones are working against the movement. All forces moving with the movement are put into the equation as positive, and all the forces acting against the movement are negative. When you are determining which forces to included you only use the ones that work in the same axis, or along a cord, to find the net force. In order to help yourself do this, drawing a FBD is useful. When there are two systems involved your use the sum of the forces to equal Mass(total) times acceleration. Commonly, in physics problems, there is a Frictional Force that acts in the opposite direction. The equation to find the MU is Ff=MU* Fn. In order to find the Fn you use the equation Sum Fy=Fn-Fg equals 0 (if the object is resting on a surface and not falling through the table.) The unit for MU is Naked! This is because the units Newton's/Newton's cancels out. I also learned why air resistance allows for terminal velocity. When the Frictional air force is equal to the gravitational force, the object can no longer accelerate, causing terminal velocity. Air resistance is caused by the interaction of a surface and the atmosphere. The surface area and the speed of the object cause for greater air resistance.
When we first learned about pulleys and tensions I had a hard time understanding how to find the tension in the string. I finally realized it was as simple as solving for Ft in my sum of forces equation. As usual, I don't always understand concepts at the first look at a concept. Frequently I leave the problem aside and then look at it later with a fresh and clean approach. Most of the time this technique works.
My problem-solving skills have improved since my last reflection. I think I have put more effort into understanding the material and the homework assignments. I have made my learning of the material rather than completion a priority. I think that I have become more systematic with my problem solving than I used to be. In the past my thoughts and problem solving methods have been very unorthodox, but now I use the same thoughts, but organize them on the page better. I have become less careless in my work, and I think this has caused me to enjoy math and physics more.
Thank you for your comments!
When we first learned about pulleys and tensions I had a hard time understanding how to find the tension in the string. I finally realized it was as simple as solving for Ft in my sum of forces equation. As usual, I don't always understand concepts at the first look at a concept. Frequently I leave the problem aside and then look at it later with a fresh and clean approach. Most of the time this technique works.
My problem-solving skills have improved since my last reflection. I think I have put more effort into understanding the material and the homework assignments. I have made my learning of the material rather than completion a priority. I think that I have become more systematic with my problem solving than I used to be. In the past my thoughts and problem solving methods have been very unorthodox, but now I use the same thoughts, but organize them on the page better. I have become less careless in my work, and I think this has caused me to enjoy math and physics more.
Thank you for your comments!
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