Topic: astronomy
Topic: event time
Topic: general relativity
Topic: history of science
Topic: law of nature
Topic: local vs. global
Topic: reality is a machine
Topic: physics
Topic: reductionism
Topic: science as experiment
Topic: science as mathematics
Topic: science as measurement
Topic: special relativity
Topic: state
Topic: time
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Subtopic: Newtonian physics explains all
Quote: the success of 19c physics lead to the belief that all phenomena can be explained in a similar way; including life and thought
| Quote: Laplace--an intelligence could know the entire universe, past and future, given sufficient information at some instant [»layzD12_1975]
| Quote: Newtonian physics assumes the existence of a real universe; relativity and quantum mechanics are based on observability [»wegnP10_1986]
| Subtopic: Newtonian is accurate in the large
Quote: in the classical limit, the quantum mechanics of a system will agree with Newtonian mechanics [»feynRP_1965]
| Subtopic: absolute space-time
Quote: Newton--time and space are immutable and absolute [»newtI_1685, OK]
| Quote: we impose the frames of time and space on nature because we find them convenient [»poinH_1905, OK]
| Quote: in Newtonian mechanics, physical reality was space and time with permanently existing material points and independent observers [»einsA_1916b]
| Quote: absolute time is not liable to change even though it may be impossible to measure due to accelerations; ought to be deducible [»newtI_1685, OK]
| Quote: God constitutes duration and space; God is eternal and infinite, omnipotent and omniscient [»newtI_1685, OK]
| Quote: automata theory and classical physics use a global, system state determined by the global, real time [»petrCA1_1966]
| Subtopic: Newton's laws
Quote: Newton's first law--a body continues in uniform motion; forces can change its state [»newtI_1685, OK]
| Quote: Newton's second law--the change of motion is proportional to the force; in the same direction [»newtI_1685, OK]
| Quote: Newton's third law--every action has equal reaction in the opposite direction [»newtI_1685, OK]
| Quote: it is by definition that 'f=ma', that action and reaction are equal and opposite, that objects remain in uniform motion [»poinH_1902, OK]
| Subtopic: orbit
Quote: Kepler reconstructed the earth's orbit from that moment every Martian year when the sun, earth, and Mars nearly form a straight line [»einsA11_1930]
| Quote: Newton proved that Kepler's 2nd law of equal areas in equal times is a direct consequence of the idea that all forces are directed exactly toward the sun [»feynRP_1963]
| Quote: Kepler's law about equal areas in equal times is the law of conservation of angular momentum when there is no torque, i.e., the force is radial [»feynRP_1963]
| Subtopic: relativity
Quote: Newton first stated the principle of relativity: the motions of bodies in a given space are independent of uniform motion of the space in a straight line [»feynRP_1963]
| Quote: Newton--only space from infinity to infinity is immovable; always same relative position [»newtI_1685, OK]
| Quote: Newton--motion and rest are only relatively distinguished [»newtI_1685, OK]
| Quote: despite the edict against the opinion that the earth moves, Galileo sided with the Copernican view and showed that it was superior [»galiG_1632]
| Quote: summary of Galileo's Dialog: experiments performed on the earth are independent of the earth's motion, celestial phenomena support the Copernican hypothesis, and the tides are due to the earth's movement [»galiG_1632]
| Quote: the celestial bodies are generable and corruptible like the earth; e.g., sun spots and the mountains on the moon as shown by the telescope [»galiG_1632]
| Quote: motion is relative to things at rest; among things that share equally in a motion, motion is as if it did not exist [»galiG_1632]
| Quote: from within a cabin below decks of a large ship, you can not distinguish standing still from moving uniformly [»galiG_1632]
| Subtopic: measurement
Quote: construct a balance with two water buckets, one above the other; equilibrium is regained after opening a hole in the upper bucket [»galiG_1638]
| Quote: mathematical analysis is primarily the study of temporal and spatial frames
| Quote: men measure all things by themselves; e.g., since we grow weary of motion, all things seek respose of its own accord
| Subtopic: field theory
Quote: classical physics requires both particles described by 6 parameters and fields described by an infinite number of parameters [»penrR_1989]
| Subtopic: proportional change
Quote: velocities are equal when the space passed is in the same proportion has as the time passed; more general than equal spaces in equal times [»galiG_1632]
| Quote: Galileo used a diagram to represent the change in velocity of an object over equal times; probably the first such diagram [»galiG_1632]
| Subtopic: displacement
Quote: proof that any solid lighter than a fluid will displace its weight [»arch_212]
| Subtopic: inertia
Quote: a body in motion stays in motion; can not stop in an instant; e.g., waves on the water [»hobbT_1651, OK]
| Quote: bodies at rest stay at rest; bodies in motion stay in motion; nothing can change itself [»hobbT_1651, OK]
| Subtopic: pendulum
Quote: a pendulum of cork and one of lead vibrate with equal frequency and hence move with equal speed [»galiG_1638]
| Quote: the upper links of a pendulum's chain attempt to travel faster than the pendulum and thus lessen the pendulum's vibrations [»galiG_1632]
| Subtopic: kinetic and potential energy
Quote: potential energy (dead force) is elementary to kinetic energy (living force)
| Quote: living force is accompanied by motion; kinetic energy
| Quote: a body's force is proportional to the product of its size and the square of its speed; the law of gravity [»leibGW4_1695]
| Subtopic: force
Quote: Newton's laws: if we study the mass times the acceleration and call the product the force, we will find that forces have some simplicity and independent properties; e.g., gravity [»feynRP_1963]
| Quote: dead force is an urge to motion; e.g., centrifugal force, gravity, centripetal force, a stretched elastic; potential energy [»leibGW4_1695]
| Quote: a body at rest will move only under a natural tendency toward some particular place [»galiG_1632]
| Quote: if a pile driver moves a pole two inches, is the effect the same as a dead weight of 1000 pounds? [»galiG_1638]
| Quote: the force of a mover and the resistance of the moved is compounded of two actions: weight and speed [»galiG_1638]
| Subtopic: continuum
Quote: for a body to acquire any degree of speed it must first pass through all gradations of lesser speed
| Quote: a moveable attains a degree of speed for just an instant in a finite time [»galiG_1638]
| Quote: there are infinitely many instants which correspond to infinitely many degrees of diminished speed
| Subtopic: acceleration due to gravity
Quote: the upward motion of thrown objects is just as natural as the downward motion due to gravity [»galiG_1632]
| Quote: when holding a rock, there is an upward impelling force that equals the downward force due to gravity [»galiG_1638]
| Quote: a projectile carried in uniform horizontal and accelerated downward motion describes a semiparabolic line [»galiG_1638]
| Quote: Galileo studied gravity by rolling a bronze ball down a long wooden beam; accuracy to a tenth of a pulse-beat [»galiG_1638]
| Quote: if moveables descend rays from a point, they form a circle of ever widening diameter; a wonderful feature of nature [»galiG_1638]
| Quote: confirmation of Galileo's experiment of rolling balls down an inclined plane with time measured by water [»settTB1_1961]
| Quote: degrees of speed acquired by the same moveable over different inclinations are the same when the heights are the same; e.g., a pendulum swings to the same height even if a nail interrupts its swing [»galiG_1638]
| Quote: if you throw an object down from the top of a tower, only the downward motion is sensible; the motion of the earth is independent [»galiG_1632]
| Quote: the acceleration of straight motion in heavy bodies proceeds according to the odd numbers beginning from one; i.e., the spaces passed over are to each other as the squares of the times [»galiG_1632]
| Quote: uniform acceleration adds on to itself equal momenta of swiftness in equal times [»galiG_1638]
| Quote: define a world-wide standard for the acceleration of naturally falling, heavy bodies; first world-wide standard of measure [»galiG_1638]
| Quote: Galileo investigated the natural acceleration of heavy things and determined its essentials; agrees with physical experiment [»galiG_1638]
| Quote: tables of amplitudes of semi-parabolas described by projectiles sent with the same impetus [»galiG_1638]
| Quote: since the maximum range occurs at 45 degrees, equal deviations from 45 degrees lead to equal ranges
| Quote: the terminal speed of a heavy body in air is less than a projectile's maximum speed; e.g., fire one lead bullet from 200 feet and another from 2 feet [»galiG_1638]
| Quote: in the void, all things fall at equal speed; air and water do not resist all objects equally [»lucr_55]
| Subtopic: certrifigal force
Quote: the tendency to throw off objects depends on the speed of revolution and not on the speed at the circumference; the earth moves too slowly to throw off stones [»galiG_1632]
| Quote: streams meander because centrifugal force is unrestrained at the surface; e.g., swirl a tea cup [»einsA1_1926]
| Subtopic: action at a distance
Quote: Newton's principle of gravitational attraction at a distance received much ridicule [»lakaI_1970]
| Subtopic: vacuum
Quote: lighter things contain more void; void is tangled up with things, and must exist [»lucr_55]
| Quote: atoms, the void, and the universe last forever; atoms are utterly solid, the void has nothing to do wih blows, and the universe has no place beyond [»lucr_55]
| Quote: measure the force of the void by weighing a piston pulling against water [»galiG_1638]
| Quote: nature's resistance to a void is part of what holds a solid together [»galiG_1638]
| Subtopic: sound
Quote: an octave is a double ratio; e.g., if a goblet jumps an octave higher, the generated waves divide into two [»galiG_1638]
| Subtopic: strength of materials
Quote: the resistance of a solid and hollow cylinder of equal weight and length is to each other as their diameters [»galiG_1638]
| Subtopic: scientific description
Quote: all experiments must be expressed in classical terms; otherwise can not communicate clearly [»bohrN_1949]
| Subtopic: no absolute time and space
Quote: time does not exist in its own right; it is part of things at motion and at rest; what happens to things in the past, present, and future [»lucr_55]
| Quote: time is nothing but the form of our internal intuition; it has empirical reality but not absolute reality [»kantI_1781, OK]
| Quote: there is no absolute space, no absolute time, no simultaneity across distance, not even geometry; these concepts are no more than a language [»poinH_1902, OK]
| Subtopic: limitation of Newtonian physics
Quote: the first indication that classical physics was wrong was Maxwell's work on specific heats; molecules have discrete energy levels [»feynRP_1963]
| Quote: Newton's laws approximate the actual quantum-mechanical laws of motion on a fine scale; Newton's laws fortunately become more accurate as the scale increases indefinitely [»feynRP_1963]
| Quote: just because an idea has held for a very long time does not make it true; for example, the theory of relativity overturned Newton's laws [»feynRP_1963]
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Related Topics
Topic: astronomy (8 items)
Topic: event time (45 items)
Topic: general relativity (47 items)
Topic: history of science (52 items)
Topic: law of nature (28 items)
Topic: local vs. global (29 items)
Topic: reality is a machine (48 items)
Topic: physics (51 items)
Topic: reductionism (51 items)
Topic: science as experiment (38 items)
Topic: science as mathematics (26 items)
Topic: science as measurement (36 items)
Topic: special relativity (73 items)
Topic: state (35 items)
Topic: time (49 items)
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