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This article deals with the history of classical mechanics.

Contents

1 Antiquity 2 Medieval thought 3 Modern age – formation of classical mechanics 4 Present 5 See also 6 Notes 7 References

Antiquity[edit] Main article: Aristotelian physics

Aristotle's laws of motion. In Physics
Physics
he states that objects fall at a speed proportional to their weight and inversely proportional to the density of the fluid they are immersed in. This is a correct approximation for objects in Earth's gravitational field moving in air or water.[1]

The ancient Greek philosophers, Aristotle
Aristotle
in particular, were among the first to propose that abstract principles govern nature. Aristotle argued, in On the Heavens, that terrestrial bodies rise or fall to their "natural place" and stated as a law the correct approximation that an object's speed of fall is proportional to its weight and inversely proportional to the density of the fluid it is falling through.[1] Aristotle
Aristotle
believed in logic and observation but it would be more than eighteen hundred years before Francis Bacon
Francis Bacon
would first develop the scientific method of experimentation, which he called a vexation of nature.[2] Aristotle
Aristotle
saw a distinction between "natural motion" and "forced motion", and he believed that in a hypothetical vacuum, there would be no reason for a body to move naturally toward one point rather than any other, and so he concluded a body in a vacuum must either stay at rest or else move indefinitely fast. In this way, Aristotle
Aristotle
was the first to approach something similar to the law of inertia. However, he believed a vacuum would be impossible because the surrounding air would rush in to fill it immediately. He also believed that an object would stop moving in an unnatural direction once the applied forces were removed. Later Aristotelians developed an elaborate explanation for why an arrow continues to fly through the air after it has left the bow, proposing that an arrow creates a vacuum in its wake, into which air rushes, pushing it from behind. Aristotle's beliefs were influenced by Plato's teachings on the perfection of the circular uniform motions of the heavens. As a result, he conceived of a natural order in which the motions of the heavens were necessarily perfect, in contrast to the terrestrial world of changing elements, where individuals come to be and pass away. Galileo
Galileo
would later observe "the resistance of the air exhibits itself in two ways: first by offering greater impedance to less dense than to very dense bodies, and secondly by offering greater resistance to a body in rapid motion than to the same body in slow motion".[3] Medieval thought[edit] French priest Jean Buridan
Jean Buridan
developed the Theory of impetus. Albert, Bishop of Halberstadt, developed the theory further. Modern age – formation of classical mechanics[edit] It wasn't until Galileo
Galileo
Galilei's development of the telescope and his observations that it became clear that the heavens were not made from a perfect, unchanging substance. Adopting Copernicus's heliocentric hypothesis, Galileo
Galileo
believed the Earth
Earth
was the same as other planets. Galileo
Galileo
may have performed the famous experiment of dropping two cannonballs from the tower of Pisa. (The theory and the practice showed that they both hit the ground at the same time.) Though the reality of this experiment is disputed, he did carry out quantitative experiments by rolling balls on an inclined plane; his correct theory of accelerated motion was apparently derived from the results of the experiments. Galileo
Galileo
also found that a body dropped vertically hits the ground at the same time as a body projected horizontally, so an Earth
Earth
rotating uniformly will still have objects falling to the ground under gravity. More significantly, it asserted that uniform motion is indistinguishable from rest, and so forms the basics of the theory of relativity. Sir Isaac Newton
Isaac Newton
was the first to unify the three laws of motion (the law of inertia, his second law mentioned above, and the law of action and reaction), and to prove that these laws govern both earthly and celestial objects. Newton and most of his contemporaries, with the notable exception of Christiaan Huygens, hoped that classical mechanics would be able to explain all entities, including (in the form of geometric optics) light. Newton's own explanation of Newton's rings avoided wave principles and supposed that the light particles were altered or excited by the glass and resonated. Newton also developed the calculus which is necessary to perform the mathematical calculations involved in classical mechanics. However it was Gottfried Leibniz
Gottfried Leibniz
who, independently of Newton, developed a calculus with the notation of the derivative and integral which are used to this day. Classical mechanics
Classical mechanics
retains Newton's dot notation for time derivatives. Leonhard Euler
Leonhard Euler
extended Newton's laws of motion
Newton's laws of motion
from particles to rigid bodies with two additional laws. After Newton, re-formulations progressively allowed solutions to a far greater number of problems. The first was constructed in 1788 by Joseph Louis Lagrange, an Italian-French mathematician. In Lagrangian mechanics the solution uses the path of least action and follows the calculus of variations. William Rowan Hamilton
William Rowan Hamilton
re-formulated Lagrangian mechanics
Lagrangian mechanics
in 1833. The advantage of Hamiltonian mechanics was that its framework allowed a more in-depth look at the underlying principles. Most of the framework of Hamiltonian mechanics can be seen in quantum mechanics however the exact meanings of the terms differ due to quantum effects. Although classical mechanics is largely compatible with other "classical physics" theories such as classical electrodynamics and thermodynamics, some difficulties were discovered in the late 19th century that could only be resolved by more modern physics. When combined with classical thermodynamics, classical mechanics leads to the Gibbs paradox
Gibbs paradox
in which entropy is not a well-defined quantity. As experiments reached the atomic level, classical mechanics failed to explain, even approximately, such basic things as the energy levels and sizes of atoms. The effort at resolving these problems led to the development of quantum mechanics. Similarly, the different behaviour of classical electromagnetism and classical mechanics under velocity transformations led to the theory of relativity. Present[edit] By the end of the 20th century, classical mechanics in physics was no longer an independent theory. Along with classical electromagnetism, it has become imbedded in relativistic quantum mechanics or quantum field theory[1]. It defines the non-relativistic, non-quantum mechanical limit for massive particles. Classical mechanics
Classical mechanics
has also been a source of inspiration for mathematicians. The realization that the phase space in classical mechanics admits a natural description as a symplectic manifold (indeed a cotangent bundle in most cases of physical interest), and symplectic topology, which can be thought of as the study of global issues of Hamiltonian mechanics, has been a fertile area of mathematics research since the 1980s. See also[edit]

Mechanics Timeline of classical mechanics

Notes[edit]

^ a b Rovelli, Carlo (2015). "Aristotle's Physics: A Physicist's Look". Journal of the American Philosophical Association. 1 (1): 23–40. doi:10.1017/apa.2014.11.  ^ Peter Pesic (March 1999). "Wrestling with Proteus: Francis Bacon
Francis Bacon
and the "Torture" of Nature". Isis. The University of Chicago Press on behalf of The History of Science Society. 90 (1): 81–94. doi:10.1086/384242. JSTOR 237475.  ^ Galileo
Galileo
Galilei, Dialogues Concerning Two New Sciences by Galileo Galilei. Translated from the Italian and Latin into English by Henry Crew and Alfonso de Salvio. With an Introduction by Antonio Favaro (New York: Macmillan, 1914). Chapter: The Motion of Projectiles

References[edit]

Truesdell, C. (1968). Essays in the History of Mechanics. Berlin, Heidelberg: Springer Berlin Heidelberg. ISBN 9783642866470.  Maddox, René Dugas ; foreword by Louis de Broglie ; translated into English by J.R. (1988). A history of mechanics (Dover ed.). New York: Dover Publications. ISBN 0-486-65632-2.  Buchwald, Jed Z.; Fox, Robert, eds. (2013). The Oxford handbook of the history of physics (First ed.). Oxford: Oxford University Press. pp. 358–405. ISBN 97

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