Historically, the first principle of relativity that was formulated was a principle of relativity of uniform motion suggested by the observation that there doesn't seem to be a phenomenon in dynamics that will allow an observer to establish a zero point of velocity, nor a preferred direction. Every choice of a zero point of velocity, a choice necessary in order to perform a calculation, constitutes a choice of reference frame. All reference frames that move with respect to each other with constant velocity and in a straight lin ...

See also:

Principle of relativity, Principle of relativity - Galilean relativity, Principle of relativity - Special relativity, Principle of relativity - General relativity

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Galileo's principle of relativity said that every choice of a zero point of velocity, a choice necessary in order to perform a calculation, constitutes a choice of reference frame. All reference frames that move with respect to each other with constant velocity and in a straight line are called inertial (or non accelerating) reference frames. The circularity of this definition is a necessity, since no preferred inertial reference frame is proposed. In Galilean relativity, reference frames are related to each other in an intuitive way: ...

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Principle of relativity, Principle of relativity - Galilean relativity, Principle of relativity - Special relativity, Principle of relativity - General relativity, Principle of relativity - references and links

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In physics, classical mechanics or Newtonian mechanics is one of the two major sub-fields of study in the science of mechanics, which is concerned with the set of physical laws governing and mathematically describing the motions of bodies and aggregates of bodies. The other sub-field is quantum mechanics. The term classical mechanics was coined in the early 20th century to describe the system of mathematical physics developed in the 400 years since the groundbreaking works of Brahe, Kepler, and Galileo,but before the dev ...

Including:

• Classical mechanics - Description of the theory
• Classical mechanics - Position and its derivatives
• Classical mechanics - Forces; Newton's second law
• Classical mechanics - Energy
• Classical mechanics - Beyond Newton's Laws
• Classical mechanics - Classical transformations
• Classical mechanics - History
• Classical mechanics - Limits of validity
• Classical mechanics - The classical approximation to special relativity
• Classical mechanics - The classical approximation to quantum mechanics
• Classical mechanics - Notes

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While in the popular mind, eternity often simply means existing for an infinite, i.e., limitless, amount of time, many have used it to refer to a timeless existence altogether outside of time. There are a number of arguments for eternity, by which proponents of the concept, principally, Aristotle, purported to prove that matter, motion, and time must have existed eternally. Eternity - Eternity as a timeless existence. Augustine of Hippo wrote that time exists only within the created universe, ...

Including:

• Eternity - Eternity as a timeless existence
• Eternity - God and eternity
• Eternity - Science and eternity
• Eternity - Symbolism and eternity

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In an exact original 1792 translation (from Latin) Newton's Second Law of Motion reads: "LAW II: The alteration of motion is ever proportional to the motive force impressed; and is made in the direction of the right line in which that force is impressed. -- If a force generates a motion, a double force will generate double the motion, a triple force triple the motion, whether that force be impressed altogether and at once, or gradually and successively. And this motion (being always directed the same way with the generating force), if ...

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Newton's laws of motion, Newton's laws of motion - Newton's first law: law of inertia, Newton's laws of motion - Newton's second law, Newton's laws of motion - Newton's third law: law of reciprocal actions, Newton's laws of motion - Importance and range of validity, Newton's laws of motion - Relationship to the conservation laws, Newton's laws of motion - Newton's second law - historical development

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Supervenience - Value. The value of a physical object to an agent is sometimes held to be supervenient upon the physical properties of the object. In aesthetics, the beauty of La Grande Jatte might supervene on the physical composition of the painting (the specific molecules that make up the painting), the artistic composition of the painting (in this case, dots), the figures and forms of the painted image, or the painted canvas as a whole. In ethics, the goodness of an act of charity might supervene on the physi ...

See also:

Supervenience, Supervenience - Examples, Supervenience - Value, Supervenience - Philosophy of mind

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Faster-Than-Light travel or communication is problematic in a universe that is consistent with Einstein's Theory of Relativity. In a hypothetical universe where Newton's laws of motion and the Galilean transformations are exact, rather than approximate, the following would be true: Space and time measurements always give the same results in every 'frame of reference' Velocities add linearly There is nothing fundamental about the wave velocity of ligh ...

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Faster-than-light, Faster-than-light - Terminology, Faster-than-light - Possibility of FTL, Faster-than-light - Option A: Ignore special relativity., Faster-than-light - Option B: Get light to go faster., Faster-than-light - Option C: Give up causality., Faster-than-light - Option D: Give up absolute relativity., Faster-than-light - Tachyons, Faster-than-light - General relativity, Faster-than-light - Apparent FTL, Faster-than-light - Moving spot of light, Faster-than-light - Relative motion, Faster-than-light - Phase velocities above c, Faster-than-light - Group velocities above c, Faster-than-light - Universal expansion, Faster-than-light - Astronomical observations, Faster-than-light - Quantum mechanics

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The following introduces the basic concepts of classical mechanics. For simplicity, it uses point particles, objects with negligible size. The motion of a point particle is characterized by a small number of parameters: its position, mass, and the forces applied to it. Each of these parameters is discussed in turn. In reality, the kind of objects which classical mechanics can describe always have a non-zero size. True point particles, such as the electron, are normally better described by quantum mechanics. Objects with non-zero size ...

See also:

Classical mechanics, Classical mechanics - Description of the theory, Classical mechanics - Position and its derivatives, Classical mechanics - Forces; Newton's second law, Classical mechanics - Energy, Classical mechanics - Beyond Newton's Laws, Classical mechanics - Classical transformations, Classical mechanics - History, Classical mechanics - Limits of validity, Classical mechanics - The classical approximation to special relativity, Classical mechanics - The classical approximation to quantum mechanics, Classical mechanics - Notes

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Theists say that God is eternally existent. How this is understood depends on which definition of eternity is used. On the one hand, God may exist in eternity, a timeless existence where categories of past, present, and future just do not apply. On the other hand, God may exist for or through eternity, or at all times, having already existed for an infinite amount of time and being expected to continue ...

See also:

Eternity, Eternity - Eternity as a timeless existence, Eternity - God and eternity, Eternity - Science and eternity, Eternity - Symbolism and eternity

Read more here: » Eternity: Encyclopedia II - Eternity - God and eternity

The modern theory of relativity provides a physical description of the universe in which the past and future may exist alongside the present. Some scientific theories of consciousness such as space-time theories of consciousness propose that the space-time continuum permits consciousness. The physics taught in most schools describes the universe in terms of Galilean relativity in which only the durationless present exists. This concept is known as present ...

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Eternity, Eternity - Eternity as a timeless existence, Eternity - God and eternity, Eternity - Science and eternity, Eternity - Symbolism and eternity

Read more here: » Eternity: Encyclopedia II - Eternity - Science and eternity

The laws of conservation of momentum, energy, and angular momentum are of more general validity than Newton's laws, since they apply to both light and matter, and to both classical and non-classical physics. In the special case of a system of material particles interacting via instantaneously transmitted forces, Newton's second law can be viewed as a definition of force, and the third law can be derived from conservation of momentum. Newton stated the third law within a world-view that assumed instantaneous action at a distance betwee ...

See also:

Newton's laws of motion, Newton's laws of motion - Newton's first law: law of inertia, Newton's laws of motion - Newton's second law, Newton's laws of motion - Newton's third law: law of reciprocal actions, Newton's laws of motion - Importance and range of validity, Newton's laws of motion - Relationship to the conservation laws, Newton's laws of motion - Newton's second law - historical development

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In the context of this article, FTL actually refers to the transmission of information or matter faster than c, a constant equal to the speed of light in a vacuum, roughly 300 million metres per second. This is not quite the same as travelling faster than light, since: There are some processes which do propagate faster than c, but which can't actually carry information (See the Apparent FTL section in this article). Light itself will travel at a speed slower than c when not in a vacuum (causing refr ...

See also:

Faster-than-light, Faster-than-light - Terminology, Faster-than-light - Possibility of FTL, Faster-than-light - Option A: Ignore special relativity., Faster-than-light - Option B: Get light to go faster., Faster-than-light - Option C: Give up causality., Faster-than-light - Option D: Give up absolute relativity., Faster-than-light - Tachyons, Faster-than-light - General relativity, Faster-than-light - Apparent FTL, Faster-than-light - Moving spot of light, Faster-than-light - Relative motion, Faster-than-light - Phase velocities above c, Faster-than-light - Group velocities above c, Faster-than-light - Universal expansion, Faster-than-light - Astronomical observations, Faster-than-light - Quantum mechanics

Read more here: » Faster-than-light: Encyclopedia II - Faster-than-light - Terminology

Faster-than-light - Moving spot of light. Processes which do not transmit information may move faster than light. A good example is a beam of light projected onto a distant surface, such as the Moon. The spot which the beam strikes is not a physical object, just a point of light. Moving it (by reorienting the beam) does not carry information between locations on the surface. To put it another way, the beam can be considered as a stream of photons; where each photon strikes the surface is determined only by the or ...

See also:

Faster-than-light, Faster-than-light - Terminology, Faster-than-light - Possibility of FTL, Faster-than-light - Option A: Ignore special relativity., Faster-than-light - Option B: Get light to go faster., Faster-than-light - Option C: Give up causality., Faster-than-light - Option D: Give up absolute relativity., Faster-than-light - Tachyons, Faster-than-light - General relativity, Faster-than-light - Apparent FTL, Faster-than-light - Moving spot of light, Faster-than-light - Relative motion, Faster-than-light - Phase velocities above c, Faster-than-light - Group velocities above c, Faster-than-light - Universal expansion, Faster-than-light - Astronomical observations, Faster-than-light - Quantum mechanics

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Newton's laws were verified by experiment and observation for over 200 years, and they are excellent approximations at the scales and speeds of everyday life. At the atomic scale, they become a poorer approximation to quantum mechanics, and at speeds comparable to the speed of light, they become a poorer approximation to relativity. Just as they fail for material objects moving at speeds close to the speed of light, they fail for light itself. Newton's first law appeared to be in the past just a special case of the second law, and it ...

See also:

Newton's laws of motion, Newton's laws of motion - Newton's first law: law of inertia, Newton's laws of motion - Newton's second law, Newton's laws of motion - Newton's third law: law of reciprocal actions, Newton's laws of motion - Importance and range of validity, Newton's laws of motion - Relationship to the conservation laws, Newton's laws of motion - Newton's second law - historical development

Read more here: » Newton's laws of motion: Encyclopedia II - Newton's laws of motion - Importance and range of validity

Lex II: Mutationem motus proportionalem esse vi motrici impressae et fieri secundum lineam rectam qua vis illa imprimitur. The rate of change of momentum of a body is equal to the resultant force acting on the body and is in the same direction. Newton's second law as originally stated in terms of momentum is 'An applied force is equal to the rate of change of momentum'. . The physical meaning of this equation is that objects int ...

See also:

Newton's laws of motion, Newton's laws of motion - Newton's first law: law of inertia, Newton's laws of motion - Newton's second law, Newton's laws of motion - Newton's third law: law of reciprocal actions, Newton's laws of motion - Importance and range of validity, Newton's laws of motion - Relationship to the conservation laws, Newton's laws of motion - Newton's second law - historical development

Read more here: » Newton's laws of motion: Encyclopedia II - Newton's laws of motion - Newton's second law

Newton's second law as originally stated in terms of momentum is 'An applied force is equal to the rate of change of momentum'. . The physical meaning of this equation is that objects interact by exchanging momentum, and they do this via a force. When the mass of the object is constant, the relation gives another useful form of the second law: where is the accelera ...

See also:

Newton's laws of motion, Newton's laws of motion - Newton's first law: law of inertia, Newton's laws of motion - Newton's second law, Newton's laws of motion - Newton's third law: law of reciprocal actions, Newton's laws of motion - Importance and range of validity, Newton's laws of motion - Relationship to the conservation laws, Newton's laws of motion - Newton's second law - historical development

Read more here: » Newton's laws of motion: Encyclopedia II - Newton's laws of motion - Newton's second law

In the context of this article, FTL actually refers to the transmission of information or matter faster than c, a constant equal to the speed of light in a vacuum, roughly 300 million metres per second. This is not quite the same as travelling faster than light, since: There are some processes which do propagate faster than c, but which can't actually carry information (See the Apparent FTL section in this article). Light itself will travel slower than c when not in a vacuum (causing refraction), and in certain materials other particles can travel faster than it (but still slower than ...

See also:

Faster-than-light, Faster-than-light - Terminology, Faster-than-light - Possibility of FTL, Faster-than-light - Option A: Ignore special relativity., Faster-than-light - Option B: Get light to go faster., Faster-than-light - Option C: Give up causality., Faster-than-light - Option D: Give up absolute relativity., Faster-than-light - Tachyons, Faster-than-light - General relativity, Faster-than-light - Apparent FTL, Faster-than-light - Moving spot of light, Faster-than-light - Relative motion, Faster-than-light - Phase velocities above c, Faster-than-light - Group velocities above c, Faster-than-light - Universal expansion, Faster-than-light - Astronomical observations, Faster-than-light - Quantum mechanics

Read more here: » Faster-than-light: Encyclopedia II - Faster-than-light - Terminology

Classical mechanics - The classical approximation to special relativity. Non-relativistic classical mechanics approximates the relativistic momentum with m0v, so it is only valid when the velocity is much less than the speed of light. For example, the relativistic cyclotron frequency of a cyclotron, gyrotron, or high voltage magnetron is given by , where fc is the classical frequency of an electron (or oth ...

See also:

Classical mechanics, Classical mechanics - Description of the theory, Classical mechanics - Position and its derivatives, Classical mechanics - Forces; Newton's second law, Classical mechanics - Energy, Classical mechanics - Beyond Newton's Laws, Classical mechanics - Classical transformations, Classical mechanics - History, Classical mechanics - Limits of validity, Classical mechanics - The classical approximation to special relativity, Classical mechanics - The classical approximation to quantum mechanics, Classical mechanics - Notes

Read more here: » Classical mechanics: Encyclopedia II - Classical mechanics - Limits of validity

Main article: History of classical mechanics The Greeks, and Aristotle in particular, were the first to propose that there are abstract principles governing nature. One of the first scientists who suggested abstract laws was Galileo Galilei who may have performed the famous experiment of dropping two cannon balls 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 apparent ...

See also:

Classical mechanics, Classical mechanics - Description of the theory, Classical mechanics - Position and its derivatives, Classical mechanics - Forces; Newton's second law, Classical mechanics - Energy, Classical mechanics - Beyond Newton's Laws, Classical mechanics - Classical transformations, Classical mechanics - History, Classical mechanics - Limits of validity, Classical mechanics - The classical approximation to special relativity, Classical mechanics - The classical approximation to quantum mechanics, Classical mechanics - Notes

Read more here: » Classical mechanics: Encyclopedia II - Classical mechanics - History

In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, it is not impossible for an object to exist which always moves faster than light. The hypothetical elementary particles that have this property are called tachyons. Their existence has neither been proven nor disproven. Tachyons are not structurally stable. The equations of relativity do allow faster than light travel, since the equations are symmetric about the velocity 'c', ...

See also:

Faster-than-light, Faster-than-light - Terminology, Faster-than-light - Possibility of FTL, Faster-than-light - Option A: Ignore special relativity., Faster-than-light - Option B: Get light to go faster., Faster-than-light - Option C: Give up causality., Faster-than-light - Option D: Give up absolute relativity., Faster-than-light - Tachyons, Faster-than-light - General relativity, Faster-than-light - Apparent FTL, Faster-than-light - Moving spot of light, Faster-than-light - Relative motion, Faster-than-light - Phase velocities above c, Faster-than-light - Group velocities above c, Faster-than-light - Universal expansion, Faster-than-light - Astronomical observations, Faster-than-light - Quantum mechanics

Read more here: » Faster-than-light: Encyclopedia II - Faster-than-light - Tachyons