Physics
Regelation is the fusion of two blocks of ice by pressure, or the "successive melting under pressure and freezing when pressure is relaxed at the interface of two blocks of ice". It is a phenomenon in which water refreezes to ice after it has been melted by pressure at a temperature below the freezing point of water. This pressure makes an ice skate form a film of water that freezes once again after the skater has passed.
The effect of impurities on melting point
A substance containing impurities usually melts at a lower temperature than the pure compound, and melts over a wide range of temperatures. In general, the smaller the range of melting temperatures, the higher the purity of the sample.
Foreign substances in a crystalline solid disrupt the repeating pattern of forces that holds the solid together. Therefore, a smaller amount of energy is required to melt the part of the solid surrounding the impurity. This explains the melting point depression (lowering) observed from impure solids. The more impure the solid is, the more its structure is disrupted, and the greater the variation in intermolecular forces in different areas of the solid. The effect: the melting temperature is lowered compared to the pure solid, and the solid melts over a wider range of temperatures.
Impurities in a solution prevent the ordering necessary to form a crystal lattice. This is why salt/water solutions will not freeze until sometimes as low as -20 °C. The concepts involved with melting points are similar. In a perfect crystal with no impurities the melting point will occur at one temperature. However when impurities are introduced there is no longer a continuous crystal structure. Instead the solid is made up of different regions, some with more crystal imperfections then others. Not surprisingly the melting point will not be...
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added: 04/30/2011
Picket Fence (Photogate)
Exp. 2
Purpose:
To measure the acceleration due to gravity by measuring the tine of fall of a picket fence dropped through a photogate.
Introduction:
You drop a picket fence, a clear stripe with black bands, through a photogate. The photogate beam is blocked by band and the time between bands becomes increasingly shorter. The computer program, Science Workshop, calculates the average speed between bands. A graph of average speeds versus time gives the acieration due to gravity.
Data:
The slope of the velocity versus time, from the graph was 9.75 m/s2. The acceleration mean, from the table display, is also 9.75m/s2.
Questions:
My slope of the velocity time plot has a .5% difference. The mean acceleration and the slope of the velocity versus tine are the same, 9.75 m/s2. Although they both differ from the accepted value, 9.8 m/s2. I think air resistance is the main cause for the difference. I expect this graph to be constant. G from this graph would be 7.94 m/s2. This acceleration has a 19% difference which is mire than likely the effect of human error. With a polynomial fit, I found the acceleration to be 9.38 m/s2.
Shoot the Target
Exp 4
Purpose:
In performing a Monkey and Hunter experiment, the target will be the monkey and the projectile launcher will be the Hunter. This is to prove that the Hunter's bullet will always hit the Monkey, as long as the Monkey is less than the range of the gun and the Monkey releases itself exactly when the Hunter shoots.
Theory:
The ball will hit the target if the Launcher is aimed directly at the hanging target.
Method:
First you must aim the launch at the center of the target. Then disarm the photogate, put the ball into the launcher and cock. Before you go any further rearm the photogate. Finally shoot the ball.
Questions:
1. The gravitational acceleration...
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added: 04/30/2011
Thomas Alva Edison was a notable inventor of his time and greatly affected the social, economical, and political world of the early 1900's. His impact was clearly seen through the rapid integration of the inventions that he promoted. Aside from the controversy about his methods of obtaining and promoting inventions, Edison was an impressive figure, and his advocacy of new technologies improved life in many ways. Widespread use of inventions such as the phonograph and the vitascope drastically changed social life for Americans, giving restless Americans new forms of entertainment. Edison's discoveries, inventions, and promotions also helped to establish new businesses, and formulated the recording and movie industry. Also, Edison's production and encouragement of the widespread use of the light bulb made it possible for businesses to run efficiently even after hours without resorting to gas lamps.
Edison was also a big name among law firms and legal affairs. His had a notorious reputation for suing competitors, accusing them of patent infringement. The U.S. Patent Office and the court had much trouble sorting out the legal dilemmas of this over-zealous inventor. Edison and his fellow inventors discovered new uses for electricity and mechanics, and their discoveries paved the way for further scientific and technological advancement. In addition, Edison's experiments lead to unexpected scientific discoveries, such as the 'Edison Effect', which was later used to develop the radio. Edison influenced the lifestyles of his contemporaries in many aspects, and the results of his inventions, discoveries, and promotions continue to have an impact on life even after his death.
Edison's contributions to the social world were notable and dramatic. His phonograph was the first machine to be able to record and mimic sounds. Edison achieved immediate fame when he first released the phonograph in 1878. Unfortunately for Edison, this phonograph had little commercial...
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added: 03/16/2011
Throughout this year, I have greatly enjoyed doing labs in Physics class. Not only did I have fun while doing these labs, but also learned a lot from them. By doing these labs, the abstract concepts that I learned by reading the textbooks came alive; I was able to experience firsthand the wonder of physics. The lab that I enjoyed the most doing was the Egg Drop Lab. It is quite obvious why anyone would like doing this lab. It was very interesting trying to come up with the container that would keep the egg from cracking. I was able to try out my own theories and see if they worked. It was also very exciting when they worked. The lab that I found the hardest to do was the Nichrome Wire Lab. I had trouble with this lab because I couldn't set up the circuit correctly. I tried every way possible, but they wouldn't work. If I fixed one wrong setup, another one would be wrong. I had to try many times before I got the right setup. The lab that helped in my understanding of physics was the Lights in Series and Parallel lab. Before doing this lab I had no clue about the differences between voltage and amps. The lab showed me that lights in series created more resistance and so lessened the amperes, and that lights in parallel drew more current and so shined just as bright as if there were one light. The lab that gave me the most understanding in math was the Ranking Frictional Forces lab. This lab involved finding the final vector of some forces. Taking this lab before learning this in pre-calculus put me ahead of my class in math. The lab that helped the most in my understanding of the topic was the Computer/Charged Particles...
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added: 01/28/2012
Albert Einstein Biographical Essay (March 14, 1879 – April 18, 1955) was a German-born theoretical physicist. He is best known for his theory of relativity and specifically mass-energy equivalence, E = mc2. Einstein received the 1921 Nobel Prize in Physics "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect."[1] Einstein's many contributions to physics include his special theory of relativity, which reconciled mechanics with electromagnetism, and his general theory of relativity, which extended the principle of relativity to non-uniform motion, creating a new theory of gravitation. His other contributions include relativistic cosmology, capillary action, critical opalescence, classical problems of statistical mechanics and their application to quantum theory, an explanation of the Brownian movement of molecules, atomic transition probabilities, the quantum theory of a monatomic gas, thermal properties of light with low radiation density (which laid the foundation for the photon theory), a theory of radiation including stimulated emission, the conception of a unified field theory, and the geometrization of physics. Works by Albert Einstein include more than fifty scientific papers and also non-scientific books.[2][3] In 1999 Einstein was named Time magazine's "Person of the Century", and a poll of prominent physicists named him the greatest physicist of all time.[4] In popular culture the name "Einstein" has become synonymous with genius. Albert Einstein was born into a Jewish family in Ulm, Württemberg, Germany. His father was Hermann Einstein, a salesman and engineer. His mother was Pauline Einstein (née Koch). In 1880, the family moved to Munich, where his father and his uncle founded a company, Elektrotechnische Fabrik J. Einstein & Cie that manufactured electrical equipment, providing the first lighting for the Oktoberfest and cabling for the Munich suburb of Schwabing. The Einsteins were not observant of Jewish religious practices, and Albert attended a Catholic elementary school. Although...
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added: 01/27/2012
Rutherford was aware of the nuclear energy trapped in the atom. He thought the energy could not be utilised efficiently and he hoped that methods would not be discovered until man was at peace with his neighbours. Discuss. In this essay I am going to discuss Rutherford's impact on science and nuclear energy. Also share some of my opinions about the usage of nuclear power. Ernest Rutherford was a physicist and a Nobel Prize winner in chemistry. He became known as the 'father' of nuclear physics. He is best known for being the first man to split the atom and the discovery of the proton. Another important fact about Rutherford's scientific career was that he mentored 9 students who went onto win Nobel Prizes later on in their life. He has left behind quite a legacy too; an element is named after him also a crater on Mars and the moon are named after him. I think what he said about the use of nuclear technology was very insightful as what he foresaw happening if the technology was indeed harnessed was correct. He was right to say that the energy could not be 'utilised efficiently' as they ended up making a devastating bomb and led to the end of the second world war but the peace was short-lived as it transformed into the cold war which involved a nuclear arms race where America and the Soviet Union made nuclear bombs bigger and better. But luckily this mass pile up of nuclear explosives did not result with a war because attacking the opposing country would mean that the destruction of the attacking country also, this was called mutually assured destruction (MAD). My stand on nuclear energy is that I disagree with the use of it. Nuclear energy is not a good choice as an energy...
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added: 12/26/2011
Big Bang Effect It is always a mystery about how the universe began, whether if and when it will end. Astronomers construct hypotheses called cosmological models that try to find the answer. There are two types of models: Big Bang and Steady State. However, through many observational evidences, the Big Bang theory can best explain the creation of the universe. The Big Bang model postulates that about 15 to 20 billion years ago, the universe violently exploded into being, in an event called the Big Bang. Before the Big Bang, all of the matter and radiation of our present universe were packed together in the primeval fireball—an extremely hot dense state from which the universe rapidly expanded.1 The Big Bang was the start of time and space. The matter and radiation of that early stage rapidly expanded and cooled. Several million years later, it condensed into galaxies. The universe has continued to expand, and the galaxies have continued moving away from each other ever since. Today the universe is still expanding, as astronomers have observed. The Steady State model says that the universe does not evolve or change in time. There was no beginning in the past, nor will there be change in the future. This model assumes the perfect cosmological principle. This principle says that the universe is the same everywhere on the large scale, at all times.2 It maintains the same average density of matter forever. There are observational evidences found that can prove the Big Bang model is more reasonable than the Steady State model. First, the redshifts of distant galaxies. Redshift is a Doppler effect which states that if a galaxy is moving away, the spectral line of that galaxy observed will have a shift to the red end. The faster the galaxy moves, the more shift it has. If...
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added: 12/24/2011
Case Study: Biomechanics and Motor Control in "Remember the Titans" Both biomechanics and motor control are extremely prevalent subjects in the film "Remember the Titans." The movie instills the basic principles of kinesiology throughout the entire story line. It is very interesting how each different position on the field is accompanied by its own sub-set of kinesiology, exemplifying the diversity of the field. Throughout the movie, biomechanics, the study of the physical movement, is essential to the skill that the players carry out. The quarterback uses various aspects of biomechanics to throw the ball, make the ball spin in a tight spiral, and estimate the position of the ball and the position of his receivers. Without all of these components working together, the quarterback would not be able to successfully complete an intended pass. In essence, the quarterback acts as the physicist, or biomechanist, on the field, dictating the velocity, acceleration, height, distance, and displacement of the football. Meanwhile, the receivers, guards, and other players on the field use different ways to employ biomechanics. The guards and center use force, velocity, and momentum to block and hold off the offensive players. The receivers use acceleration and impulse to run and complete a pass. In addition to all of the physical aspects of playing football, all of the players are constantly using muscular force to generate power in order to do work. They are readily exemplifying gait, kinetics, kinematics, and ground reaction forces among many other aspects of biomechanics. When studying football, it is imperative to strategically plan different plays. Biomechanics plays a significant role in being able to perform them. Since the game of football greatly relies on the use of physical movement, biomechanics is an integral part of the underlying basics of the game. Motor control, or the acquisition, performance, and retention of motor skills,...
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added: 11/26/2011
The purpose of the lab that was completed was to determine the validity and reliability of an electronic spirometer, using a water spirometer as a reference. Calibration is an important tool in determining whether or not an instrument is valid and reliable. The validity of an instrument is the extent to which a procedure accomplishes what it seeks out to accomplish. Validity can be determined by checking an instrument against another similar instrument. From the tests run between the two instruments, Pearson's correlation coefficient (r) can be determined. This coefficient is a statistic that quantifies the magnitude of the relationship between two separate variables. The coefficient can range from negative 1 to positive 1. If the number is closer to positive one this means that when the variable increases, so does the other one. When the coefficient is closer to negative one this means when the variable increases, the other one does the opposite. Lastly, if the coefficient is closer to zero this means there is no relationship, positive or negative. The coefficient r can be determined from the following equation: r = N(sumXY)(sumY)/ ¡îN(sum x©÷-(sum x)©÷)(N)(sum y©÷-(sum y)©÷). The coefficient r can then be used to determine the shared variance between the two variables. Shared variance can be determined by the following equation: Shared Variance = r©÷*100. If the shared variance is 75% or better, this means there is a high correlation between the two variables. If the shared variance is between 50-75%, this means there is a moderate correlation between the two variables. Finally, if the shared variance is below 25%, this means there is a low correlation. The reliability of a procedure is also very important. The reliability is the ability of an instrument or procedure to reproduce duplicate measurements. The reliability of a procedure is also calculated...
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added: 11/24/2011
Introduction Chapter 3, "Capacitance," contains laboratory experiments designed to explore the relationship between voltage and the amount of charge stored in an object. These experiments involve measuring electrical properties of capacitors in series, in parallel, while charging, discharging, and at varying widths between the surfaces. Hands-on experience and resulting data should provide insight into the nature of capacitance. Theory In order to charge an object, a certain amount of energy is required to transfer charge to that object. The energy per unit of charge is called voltage. Given a certain voltage, charge can be transferred to an object until the amount of energy that is required to add more charge exceeds the energy potential. A derived unit is useful for expressing the capacity of charge (in Coulombs) that can be transferred to an object per unit of voltage (in Volts). Therefore, a unit of capacitance called the Farad exists, and is defined as C = Q/V. A capacitor comprised of two parallel surfaces will have a capacitance equal to 8.85 ρF/m, times the area of one of the plates, divided by the distance between them. When sharing the charge applied to one capacitor with a second capacitor, charge is conserved, therefore Vf * (C1 + C2) = Vi * C1. When discharging a capacitor through a resistor, V(t) = V0 * e-t/RC. When charging a capacitor through a resistor, V(t) = Vf – Vf * e-t/RC. Experiments 3.5.2: Charging a Capacitor This experiment required a 9V battery, a voltmeter, and voltage a follower that were assembled in this way: The battery and voltage follower ground contacts were connected to the volt meter ground, while the voltage follower output was connected to the positive terminal of the volt meter. To measure the voltage across the 0.033 μF capacitor, I connected one end of the capacitor to the positive lead...
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added: 01/24/2012
Since its inception, science relied on predictability and order. The true beauty of science was its uncanny ability to find patterns and regularity in seemingly random systems. For centuries the human mind as easily grasped and mastered the concepts of linearity. Physics illustrated the magnificent order to which the natural world obeyed. If there is a God he is indeed mathematical. Until the 19th century Physics explained the processes of the natural world successfully, for the most part. There were still many facets of the universe that were an enigma to physicists. Mathematicians could indeed illustrate patterns in nature but there were many aspects of Mother Nature that remained a mystery to Physicists and Mathematicians alike. Mathematics is an integral part of physics. It provides an order and a guide to thinking; it shows the relationship between many physical phenomenons. The error in mathematics until that point was linearity. "Clouds are not spheres, mountains are not cones, bark is not smooth, nor does lightning travel in a straight line." - Benoit Mandlebrot. Was it not beyond reason that a process, which is dictated by that regularity, could master a world that shows almost no predictability whatsoever? A new science and a new kind of mathematics were developed that could show the universe's idiosyncrasies. This new amalgam of mathematics and physics takes the order of linearity and shows how it relates to the unpredictability of the world around us. It is called Chaos Theory. The secular definition of chaos can be misleading when the word is used in a scientific context. As defined by Webster's dictionary chaos is total disorder. That may lead one to believe that chaos theory is indeed the study of total disorder, which it truly is not. In 1986 at a prestigious conference on Chaos another definition for...
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added: 10/28/2011
CRITIQUING BRADLEY Description: This paper critiques Bradley's arguments in his writing 'The Unreality of Space and Time.' This paper argues against Bradley's position using all logical methods necessary. Critiquing Bradley In his article, The Unreality of Space and Time, F. H. Bradley argues that space and time, as they exhibit themselves, are unreal. For Bradley space and time are unreal because they both possess necessary, yet contradictory characteristics. At this time we will depart from directly addressing the issue of time and restrict ourselves to dealing solely with the issue of space, but note that the conclusion and key premises are uniform to both issues. For Bradley the problem with space is that it is necessarily both ending and endless. Essential to its being space must continue to an end which it cannot possess. Though unexplained, the contradiction is revealed. Space, either how it is exhibited or how it is perceived is self-contradictory and therefore unreal. In explanation Bradley presents the following argument: Space is a relation. That is to say space is an association- a connection between things. This associative nature of space derives from that which constitutes space. For Bradley space consists of parts of space in relation to each other. To grasp this premise you might consider any amount of space and imagine that space divide in half. These two halves of space exist in relation to each other. Either or both of these halves could further be divided endlessly into oblivion. The picture one then should have is innumerable parts of space in relation to each other continuing to no final limit. These infinite relational parts of space constitute the relation that is space, the assumption being that space is, what it is constituted of. A problem arises out of this because if space is a relation it is...
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added: 01/31/2012
Gravity is the key to the Earth's rising and falling tides. The combined gravitational effects of the Sun and the Moon constantly pull the world's oceans in different directions and create tidal effects. But there are several other factors that complicate this basic process. Friction, the Earth's rotation, the tilt of its axis and the gravitational pull given off by the Sun and Moon that affects Earth's atmosphere. These forces together conspire to make our planet's oceans into a battleground. These forces tug the oceans this way and that way around the globe, thus creating high tides and low tides. The Moon's gravity stretches the earth into an oval. The effect is so tiny that the solid parts of the planet are distorted by little more than eight inches. But because of of water's fluidity, the effect on the oceans is more noticeable. At the point on the Earth directly beneath the Moon, the ocean is tugged into a bulge of high water. At the same time, a second tidal bulge forms on the opposite side of the planet. This is partly a result of the centrifugal force created by the Moon and Earth's combined rotation around their common center of mass, a theoretical point called the barycenter. Because the Earth spins on its axis once every 24 hours, the two bulges sweep around the planet in waves, creating two high tides per day at every point on the globe. But the twice daily cycle is complicated by he fact that the Earth is tilted, which puts the Moon alternately to the north and south of the equator. This creates slight differences between the two tide each day and adds a daily set of local variations to this natural rhythm. A further complication is added by the Sun, whose gavational pull on the...
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added: 01/18/2012
Archimedes, Sophocles, Hitler, Peter, and Orwell are just some of the few men in history that have tried to predict the future, with may of them predicting the downfall of civilization. But, although many of these great thinkers have come startlingly close to the stark reality in which we live. Many have argued the opinion that our culture most resembles that of Orwell's creation, but I disagree for a number of very important and relevant reasons.
First, Orwell feared that censorship would be rampant in society, with government controlling every single printed piece of paper. This is certainly not so, especially with many journalistic companies printing negative opinions of the government. Plus, why would the government really have to censor articles in this day and age? A poll done by the Associated Press showed that over thirty percent of teenagers thought our current president was Al Gore, and I would bet anything that the typical high school senior has no idea what 1984 and Brave New World are. I fear that within the next two generations the literacy rate will take a dramatic fall off of its current perch, just as Huxley has suggested - people will not want to read anymore.
Furthermore, how do most people generally spend most of their time? Pleasuring themselves. Our culture is no longer immersed in trying to better itself. It is mostly concerned with "playtime," or, if we do better ourselves, it is usually in a form that exerts more physical pleasure. In Orwell's vision, there was no pleasure. People were driven by fear and unmercifulness. While, in Huxley's revelation, society was driven by pleasure, much like ours is today. With crack, cocaine, pot, smack, ludes, horse, and Whiffy Puff whipped cream, we are a people that thrives on the "10-minute high." Just as drugs...
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added: 10/14/2011
Isaac Newton was born on Christmas day in 1642, in Lincolnshire, England. Newton attended Trinity College in 1661 and had both his Bachelor of Arts and his Master of Arts by 1669. That same year he became the associate of the French Academy of Sciences. He was elected to Parilment, then appointed a warden, and finally, President of the Royal Society. Newton was a master of science and mathematics. He discovered calculus, before Leibniz' became popular. Perhaps Newton's most popular discovery, though, was gravity. As the story goes, Sir Isaac Newton was resting under a tree one day in his garden, when an apple fell from it and hit him on the head. Thus, he discovered gravity. The earth's gravitational pull pulls objects toward it. However, many people believe that this is only a myth created to simply illustrate Newton's discovery. Along with Newton's many discoveries, the three laws of motion are famous. These include inertia, acceleration, and the idea that for every action, there is an equal and opposite reaction. Inertia is the idea that a body in motion will remain in motion, and a body at rest will remain at rest. For example, if I were to throw a baseball into the air, it would keep going until grasvity pulled it back down to earth. However, if I left it sitting on a table, it would lie there until some kind of force were to move it. If I were to push a skateboard across the floor with all of my might, the skateboard would accelerate more than if I gave it a light shove, simply because there was more force behind it. More force = more acceleration. If I were sitting on a swing and someone were to grab hold of the swing, pull it backwards, and release,...
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added: 10/31/2011
Since the beginning of time, energy has pervaded our earth. These days we rely on it to advance in our technological developments. We also need energy for a variety of other things such as: to keep our bodies alive and healthy, to run our machines and other technical devices, we also rely on energy to keep warm in winter and cool in summer. Energy is the ability to do work. People and other things can run out of energy (e.g. a marathon runner) in which case they can no longer have the ability to do work. In a mechanical situation, if a machine has energy it has the ability to apply a force to another body. There are many different forms of energy and there are many different places by which energy can be gathered. Forms of energy include: Potential energy, kinetic energy, gravitational potential energy, elastic potential energy and there are many more. Energy can be gathered in many ways using our natural recourses from the environment, for example: solar energy (from the sun) and hydroelectricity (where electricity is gathered by rushing water) Hydroelectricity is when electricity is generated by rotating coils of wire (rotors) between the poles of a magnet. The rotors are turned by rushing water falling over them. In a hydroelectric plant, water in usually stored in a damn. As the water falls down and rushes over the vanes connected to the rotors it looses gravitational potential energy and gains kinetic energy. As the metal wire rotates around the magnet it generates electricity which is then sent along power lines to all areas of the city or town. Here is a description of the transformation of energy as a pole-vaulter completes a jump. Firstly, when the pole-vaulter runs forward the muscles in the legs are doing work as...
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added: 02/07/2012
The idea of utilizing the physical principle of reaction on a large scale by means of rockets is usually attributed to China in the thirteenth century. Not until after the Second World War, however, did rocket technology mature to a state which made the idea of space travel a practical possibility, owing largely to a giant step forward during the war itself. Although earliest models of the steam turbine date back as early as the 17th century, practical applications of the turbine engine had to wait until the turn of the 20th century. Today, the gas turbine engine is the most widespread and most effective method of aircraft propulsion, having almost totally displaced the reciprocating engine, which, up to the 1960s, was the common power source in aviation. There are four types of engines I will be talking about; the turbojet, turbofan, turboprop, or the turbo shaft. The gas turbine represents one of the most technological achievements in aviation, the successful introduction of which made possible a tremendous acceleration of progress in all fields of aviation. Some of the historical milestones that are major steps toward turbine engine development, ending in the use of the gas turbine for aircraft propulsion are as follows: 1687 - the English philosopher and mathematician Sir Isaac Newton formulates three laws of motion which form the basis of modern jet propulsion, according to which: 1) a body remains either at rest, or in motion of constant velocity, unless an external force acts on the body; 2) the sum of forces acting on a body equals the product of the body's mass times acceleration produced by these forces ( i.e. force = mass times acceleration); 3) for every force acting on a body, the body exerts a force of equal magnitude and opposite direction along the same line as the original force. 1791 -...
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added: 12/22/2011
Do you wan know about Quantum mechanics, you can find things everywhere? You don't know where to start? Right answer is Being from your mind. Description of the theory There are a number of mathematically equivalent formulations of quantum mechanics. One of the oldest and most commonly used formulations is the transformation theory invented by Cambridge theoretical physicist Paul Dirac, which unifies and generalizes the two earliest formulations of quantum mechanics, matrix mechanics (invented by Werner Heisenberg) and wave mechanics (invented by Erwin Schrödinger). In this formulation, the instantaneous state of a quantum system encodes the probabilities of its measurable properties, or "observables". Examples of observables include energy, position, momentum, and angular momentum. Observables can be either continuous (e.g., the position of a particle) or discrete (e.g., the energy of an electron bound to a hydrogen atom). Generally, quantum mechanics does not assign definite values to observables. Instead, it makes predictions about probability distributions; that is, the probability of obtaining each of the possible outcomes from measuring an observable. Naturally, these probabilities will depend on the quantum state at the instant of the measurement. There are, however, certain states that are associated with a definite value of a particular observable. These are known as "eigenstates" of the observable ("eigen" meaning "own" in German). In the everyday world, it is natural and intuitive to think of everything being in an eigenstate of every observable. Everything appears to have a definite position, a definite momentum, and a definite time of occurrence. However, Quantum Mechanics does not pinpoint the exact values for the position or momentum of a certain particle in a given space in a finite time, but, rather, it only provides a range of probabilities of where that particle might be. Therefore, it became necessary to use different words for a) the state of something having...
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added: 02/20/2012
Do you wan know about Quantum mechanics, you can find things everywhere? You don't know where to start? Right answer is Being from your mind Description of the theory There are a number of mathematically equivalent formulations of quantum mechanics. One of the oldest and most commonly used formulations is the transformation theory invented by Cambridge theoretical physicist Paul Dirac, which unifies and generalizes the two earliest formulations of quantum mechanics, matrix mechanics (invented by Werner Heisenberg) and wave mechanics (invented by Erwin Schrödinger). In this formulation, the instantaneous state of a quantum system encodes the probabilities of its measurable properties, or "observables". Examples of observables include energy, position, momentum, and angular momentum. Observables can be either continuous (e.g., the position of a particle) or discrete (e.g., the energy of an electron bound to a hydrogen atom). Generally, quantum mechanics does not assign definite values to observables. Instead, it makes predictions about probability distributions; that is, the probability of obtaining each of the possible outcomes from measuring an observable. Naturally, these probabilities will depend on the quantum state at the instant of the measurement. There are, however, certain states that are associated with a definite value of a particular observable. These are known as "eigenstates" of the observable ("eigen" meaning "own" in German). In the everyday world, it is natural and intuitive to think of everything being in an eigenstate of every observable. Everything appears to have a definite position, a definite momentum, and a definite time of occurrence. However, Quantum Mechanics does not pinpoint the exact values for the position or momentum of a certain particle in a given space in a finite time, but, rather, it only provides a range of probabilities of where that particle might be. Therefore, it became necessary to use different words for a) the state of something having...
pages: 7 (words: 1697)
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added: 01/30/2012
Describe the physics involved in the safety features in cars. Introduction Every minute, on average, at least two people die in a crash. If you read this essay from start to finish, 20 or more deaths will have occurred across the globe by the time you are done. Road traffic injuries represent about 25% of worldwide injury-related deaths (the leading cause) with an estimated 1.2 million deaths (2004) each year as said by the World Health Organization. Car crashes will also injure at least 10 million people this year, two or three million of them seriously. All told, the hospital bills, damaged property, and other costs will add up to 1-3 percent of the world's gross domestic product, according to the Paris-based Organization for Economic Cooperation and Development. For the United States alone, the tally will amount to roughly US $200 billion. This essay will discuss how engineers have been chipping away at these staggering numbers over the past 50 years. History Car safety has been an issue since the automobile was first invented, and was highlighted when Nicolas-Joseph Cugnot crashed his steam-powered "Fardier" against a wall in 1771.One of the earliest recorded automobile fatalities was Mary Ward, on August 31, 1869 in Parsonstown, Ireland. In the 1940's there was much work being done with safety in airplanes. A lot of this work focused on the take off and landing process, as this was were most plane crashes occurred. This resulted in many improvements with the overall workings of the planes, such as brakes and engines, but also resulted in many safety features being created for the inside of the plane and its passengers. This research was the first of its kind, and many of its results started to flow over into the car-making field, and before long, safety features in cars became an industry...
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added: 10/31/2011