motion

mo·tion

M0440700 (mō′shən)n.1. The act or process of changing position or place.2. A meaningful or expressive change in the position of the body or a part of the body; a gesture.3. Active operation: set the plan in motion.4. The ability or power to move: lost motion in his arm.5. The manner in which the body moves, as in walking.6. A prompting from within; an impulse or inclination: resigned of her own motion.7. Music Melodic ascent and descent of pitch.8. Law An application made to a court for an order or a ruling.9. A formal proposal put to the vote under parliamentary procedures.10. a. A mechanical device or piece of machinery that moves or causes motion; a mechanism.b. The movement or action of such a device.v. mo·tioned, mo·tion·ing, mo·tions v.tr.1. To direct by making a gesture: motioned us to our seats.2. To indicate by making a gesture; signal: motioned that he was ready.3. To make a motion (that something should happen).v.intr. To signal by making a gesture: motioned to her to enter.Idiom: go through the motions To do something in a mechanical manner indicative of a lack of interest or involvement.

[Middle English mocioun, from Old French motion, from Latin mōtiō, mōtiōn-, from mōtus, past participle of movēre, to move; see meuə- in Indo-European roots.]

motion

(ˈməʊʃən) n1. (General Physics) the process of continual change in the physical position of an object; movement: linear motion. 2. (Physiology) a movement or action, esp of part of the human body; gesture3. (Physiology) a. the capacity for movementb. a manner of movement, esp walking; gait4. (Psychology) a mental impulse5. (Parliamentary Procedure) a formal proposal to be discussed and voted on in a debate, meeting, etc6. (Law) law an application made to a judge or court for an order or ruling necessary to the conduct of legal proceedings7. (Physiology) a. the evacuation of the bowelsb. excrement8. (Mechanical Engineering) a. part of a moving mechanismb. the action of such a part9. (Music, other) music the upward or downward course followed by a part or melody. Parts whose progressions are in the same direction exhibit similar motion, while two parts whose progressions are in opposite directions exhibit contrary motion. See also parallel³10. go through the motions a. to act or perform the task (of doing something) mechanically or without sincerityb. to mimic the action (of something) by gesture11. in motion operational or functioning (often in the phrases set in motion, set the wheels in motion)vb (when tr, may take a clause as object or an infinitive) to signal or direct (a person) by a movement or gesture[C15: from Latin mōtiō a moving, from movēre to move] ˈmotional adj

Motion

(ˈməʊʃən) n (Biography) Sir Andrew. born 1952, British poet and biographer; his collections include Pleasure Steamers (1978) and Public Property (2002): poet laureate (1999–2009)

mo•tion

(ˈmoʊ ʃən)

n. 1. the action or process of moving or of changing place or position; movement. 2. power of movement, as of a living body. 3. the manner of moving the body in walking; gait. 4. a bodily movement or change of posture; gesture. 5. a formal proposal, esp. one made to a deliberative assembly. 6. an application made to a court or judge for an order, ruling, or the like. 7. an inward prompting or impulse; inclination. 8. melodic progression from one pitch to another. 9. Mach. a. a piece of mechanism with a particular action or function. b. the action of such a mechanism. 10. in motion, in active operation; moving. v.t. 11. to direct by a significant motion or gesture, as with the hand. v.i. 12. to make a meaningful motion, as with the hand. [1350–1400; Middle English mocio(u)n < Latin mōtiō=mō-, variant s. of movēre to move + -tiō -tion] mo′tion•less, adj. mo′tion•less•ly, adv. mo′tion•less•ness, n.

Motion

See also travel.
apheliotropismthe tendency of some plants to grow in a direction away from the sun.apogeotropismthe tendency of some plants to grow away from the earth and the pull of gravity. — apogeotropic, adj.bradykinesia, bradykinesisslowness of movement. — bradykinetic, adj.chemotaxisthe property of some plants and animals of moving toward or away from certain chemicals.chemotropismgrowth or motion in response to a chemical stimulus. — chemotropic, adj.diatropismthe capacity or tendency of some plants to adopt a position transverse to the line of force of an external stimulus. — diatropic, adj.dromophobiakinetophobia.galvanotropismgrowth or movement of an organism in response to an electric current. — galvanotropic, adj.geotaxisthe movement of an organism in response to the force of gravity.kinematicsthe study of the motion of bodies considered independently of external forces. Also called phoronomy. — kinematic, adj.kinesomaniaa mania for movement.kineticsthe branch of physics that studies the motion of masses in relation to the forces acting on them.kinetophobiaan abnormal fear or dislike of motion. Also called dromophobia.phoronomykinematics.photokinesismovement of bodies, organisms, etc., in response to the stimulus of light. — photokinetic, adj.phototaxis, phototaxythe movement of an organism away from or toward a source of light. — phototactic, adj.phototropismmotion in a particular direction under the stimulus of light, as exhibited by certain plants, organisms, etc. — phototropic, adj.rheotaxisthe tendency of certain living things to move in response to the mechanical stimulus of a current of water.stereotaxisorientation or movement of an organism in response to the stimulus of a solid object. Cf. stereotropism. — stereotactic, adj.stereotropismgrowth or movement determined by contact with a solid. Also called thigmotropism. Cf. stereotaxis. — stereotropic, adj.tachophobiaan abnormal fear of speed.thigmotropismstereotropism. — thigmotropic, adj.trochilicsRare. the science of rotary motion. — trochilic, adj.trophotropismthe movement of cells in relation to food or nutritive matter. — trophotropic, adj.tropismthe tendency of a plant, animal, or part to move or turn in response to an external stimulus, as sunlight or temperature. — tropistic, adj.

motion

Past participle: motioned
Gerund: motioning

Imperative
motion
motion

Present
I motion
you motion
he/she/it motions
we motion
you motion
they motion

Preterite
I motioned
you motioned
he/she/it motioned
we motioned
you motioned
they motioned

Present Continuous
I am motioning
you are motioning
he/she/it is motioning
we are motioning
you are motioning
they are motioning

Present Perfect
I have motioned
you have motioned
he/she/it has motioned
we have motioned
you have motioned
they have motioned

Past Continuous
I was motioning
you were motioning
he/she/it was motioning
we were motioning
you were motioning
they were motioning

Past Perfect
I had motioned
you had motioned
he/she/it had motioned
we had motioned
you had motioned
they had motioned

Future
I will motion
you will motion
he/she/it will motion
we will motion
you will motion
they will motion

Future Perfect
I will have motioned
you will have motioned
he/she/it will have motioned
we will have motioned
you will have motioned
they will have motioned

Future Continuous
I will be motioning
you will be motioning
he/she/it will be motioning
we will be motioning
you will be motioning
they will be motioning

Present Perfect Continuous
I have been motioning
you have been motioning
he/she/it has been motioning
we have been motioning
you have been motioning
they have been motioning

Future Perfect Continuous
I will have been motioning
you will have been motioning
he/she/it will have been motioning
we will have been motioning
you will have been motioning
they will have been motioning

Past Perfect Continuous
I had been motioning
you had been motioning
he/she/it had been motioning
we had been motioning
you had been motioning
they had been motioning

Conditional
I would motion
you would motion
he/she/it would motion
we would motion
you would motion
they would motion

Past Conditional
I would have motioned
you would have motioned
he/she/it would have motioned
we would have motioned
you would have motioned
they would have motioned

Thesaurus

Noun	1.	motion - the use of movements (especially of the hands) to communicate familiar or prearranged signalsgesturevisual communication - communication that relies on visionsign - a gesture that is part of a sign languagegesticulation - a deliberate and vigorous gesture or motionbeck - a beckoning gesturefacial expression, facial gesture - a gesture executed with the facial musclesflourish - a showy gesture; "she entered with a great flourish"high-five - a gesture of greeting or elation; one person's upraised palm slaps the upraised palm of another personprevious question - a motion calling for an immediate vote on the main question under discussion by a deliberative assemblyshrug - a gesture involving the shoulderswafture, waving, wave - the act of signaling by a movement of the handV sign - a sign (for victory); making a V with the index and middle fingersnod - a sign of assent or salutation or commandbowing, obeisance, bow - bending the head or body or knee as a sign of reverence or submission or shame or greetingsign of the cross - a gesture with the right hand moving to form a cross; used by Catholics as a profession of faithcurtsey, curtsy - bending the knees; a gesture of respect made by women
	2.	motion - a natural event that involves a change in the position or location of somethingmovementhappening, natural event, occurrence, occurrent - an event that happenscrustal movement, tectonic movement - movement resulting from or causing deformation of the earth's crustapproaching, approach - the event of one object coming closer to anotherpassing, passage - the motion of one object relative to another; "stellar passings can perturb the orbits of comets"deflexion, deflection - the movement of the pointer or pen of a measuring instrument from its zero positionbending, bend - movement that causes the formation of a curvechange of location, travel - a movement through space that changes the location of somethingundulation, wave - (physics) a movement up and down or back and forthjitter - a small irregular movementperiodic motion, periodic movement - motion that recurs over and over and the period of time required for each recurrence remains the sameheave - (geology) a horizontal dislocationbacklash, rebound, recoil, repercussion - a movement back from an impactrecoil, kick - the backward jerk of a gun when it is firedseek - the movement of a read/write head to a specific data track on a diskwring, squeeze - a twisting squeeze; "gave the wet cloth a wring"cam stroke, stroke, throw - the maximum movement available to a pivoted or reciprocating piece by a camturning, turn - a movement in a new direction; "the turning of the wind"wrench, twist - a jerky pulling movementundulation - wavelike motion; a gentle rising and falling in the manner of wavesmoving ridge, wave - one of a series of ridges that moves across the surface of a liquid (especially across a large body of water)wobble - an unsteady rocking motionwhirl, commotion - confused movement; "he was caught up in a whirl of work"; "a commotion of people fought for the exits"Brownian motion, Brownian movement, pedesis - the random motion of small particles suspended in a gas or liquid
	3.	motion - a change of position that does not entail a change of location; "the reflex motion of his eyebrows revealed his surprise"; "movement is a sign of life"; "an impatient move of his hand"; "gastrointestinal motility"movement, motility, movechange - the action of changing something; "the change of government had no impact on the economy"; "his change on abortion cost him the election"abduction - (physiology) moving of a body part away from the central axis of the bodyadduction - (physiology) moving of a body part toward the central axis of the bodyagitation - the act of agitating something; causing it to move around (usually vigorously)body English - a motion of the body by a player as if to make an object already propelled go in the desired directioncircumduction - a circular movement of a limb or eyedisturbance - the act of disturbing something or someone; setting something in motionfetal movement, foetal movement - motion of a fetus within the uterus (usually detected by the 16th week of pregnancy)flit, dart - a sudden quick movementgesture - motion of hands or body to emphasize or help to express a thought or feelingheadshake, headshaking - the act of turning your head left and right to signify denial or disbelief or bemusement; "I could tell from their headshakes that they didn't believe me"inclining, inclination - the act of inclining; bending forward; "an inclination of his head indicated his agreement"everting, eversion, inversion - the act of turning inside outupending, inversion - turning upside down; setting on endjerking, jolt, saccade, jerk - an abrupt spasmodic movementkicking, kick - a rhythmic thrusting movement of the legs as in swimming or calisthenics; "the kick must be synchronized with the arm movements"; "the swimmer's kicking left a wake behind him"kneel, kneeling - supporting yourself on your kneespitching, lurch, pitch - abrupt up-and-down motion (as caused by a ship or other conveyance); "the pitching and tossing was quite exciting"eye movement - the movement of the eyesopening - the act of opening something; "the ray of light revealed his cautious opening of the door"prostration - the act of assuming a prostrate positionreaching, stretch, reach - the act of physically reaching or thrusting outreciprocation - alternating back-and-forth movementreclining - the act of assuming or maintaining a reclining positionretraction - the act of pulling or holding or drawing a part back; "the retraction of the landing gear"; "retraction of the foreskin"retroflection, retroflexion - the act of bending backwardrotary motion, rotation - the act of rotating as if on an axis; "the rotation of the dancer kept time with the music"closing, shutting - the act of closing somethingsitting - the act of assuming or maintaining a seated position; "he read the mystery at one sitting"posing, sitting - (photography) the act of assuming a certain position (as for a photograph or portrait); "he wanted his portrait painted but couldn't spare time for the sitting"snap - the act of snapping the fingers; movement of a finger from the tip to the base of the thumb on the same hand; "he gave his fingers a snap"squatting, squat - the act of assuming or maintaining a crouching position with the knees bent and the buttocks near the heelssweep - a movement in an arc; "a sweep of his arm"toss - an abrupt movement; "a toss of his head"vibration, quivering, quiver - the act of vibratingwave - a movement like that of a sudden occurrence or increase in a specified phenomenon; "a wave of settlers"; "troops advancing in waves"flutter, waver, flicker - the act of moving back and forthstanding - the act of assuming or maintaining an erect upright positionstraddle, span - the act of sitting or standing astridestroke - a single complete movementsquirm, wiggle, wriggle - the act of wigglingeurhythmics, eurhythmy, eurythmics, eurythmy - the interpretation in harmonious bodily movements of the rhythm of musical compositions; used to teach musical understanding
	4.	motion - a state of change; "they were in a state of steady motion"state - the way something is with respect to its main attributes; "the current state of knowledge"; "his state of health"; "in a weak financial state"quivering, shakiness, trembling, vibration, shaking, palpitation, quiver - a shaky motion; "the shaking of his fingers as he lit his pipe"perpetual motion - motion that continues indefinitely without any external source of energy; impossible in practice because of frictionprecession - the motion of a spinning body (as a top) in which it wobbles so that the axis of rotation sweeps out a conestream, flow - something that resembles a flowing stream in moving continuously; "a stream of people emptied from the terminal"; "the museum had planned carefully for the flow of visitors"lifelessness, motionlessness, stillness - a state of no motion or movement; "the utter motionlessness of a marble statue"
	5.	motion - a formal proposal for action made to a deliberative assembly for discussion and vote; "he made a motion to adjourn"; "she called for the question"questionproposal - something proposed (such as a plan or assumption)
	6.	motion - the act of changing location from one place to another; "police controlled the motion of the crowd"; "the movement of people from the farms to the cities"; "his move put him directly in my path"movement, movechange - the action of changing something; "the change of government had no impact on the economy"; "his change on abortion cost him the election"coming, approach, approaching - the act of drawing spatially closer to something; "the hunter's approach scattered the geese"forward motion, onward motion, advancement, progress, progression, procession, advance - the act of moving forward (as toward a goal)locomotion, travel - self-propelled movementlunge, lurch - the act of moving forward suddenlytravel, traveling, travelling - the act of going from one place to another; "he enjoyed selling but he hated the travel"chase, pursual, pursuit, following - the act of pursuing in an effort to overtake or capture; "the culprit started to run and the cop took off in pursuit"ascending, rise, ascent, ascension - the act of changing location in an upward directiondescent - the act of changing your location in a downward directionswinging, vacillation, swing - changing location by moving back and forthreturn - the act of going back to a prior location; "they set out on their return to the base camp"glide, coast, slide - the act of moving smoothly along a surface while remaining in contact with it; "his slide didn't stop until the bottom of the hill"; "the children lined up for a coast down the snowy slope"slippage - failing to hold or slipping out of place; "the knots allowed no slippage"flow, stream - the act of flowing or streaming; continuous progressioncrawl - a very slow movement; "the traffic advanced at a crawl"hurrying, speeding, speed - changing location rapidlydisplacement, translation - the act of uniform movementshifting, shift - the act of moving from one place to another; "his constant shifting disrupted the class"rush, rushing, haste, hurry - the act of moving hurriedly and in a careless manner; "in his haste to leave he forgot his book"maneuver, manoeuvre, play - a deliberate coordinated movement requiring dexterity and skill; "he made a great maneuver"; "the runner was out on a play by the shortstop"migration - the movement of persons from one country or locality to another
	7.	motion - an optical illusion of motion produced by viewing a rapid succession of still pictures of a moving object; "the cinema relies on apparent motion"; "the succession of flashing lights gave an illusion of movement"apparent motion, apparent movement, movementoptical illusion - an optical phenomenon that results in a false or deceptive visual impression
Verb	1.	motion - show, express or direct through movement; "He gestured his desire to leave"gesticulate, gesturewink - signal by winking; "She winked at him"exsert, hold out, stretch forth, stretch out, put out, extend - thrust or extend out; "He held out his hand"; "point a finger"; "extend a hand"; "the bee exserted its sting"shrug - raise one's shoulders to indicate indifference or resignationclap, spat - clap one's hands together; "The children were clapping to the music"communicate, intercommunicate - transmit thoughts or feelings; "He communicated his anxieties to the psychiatrist"applaud, acclaim, clap, spat - clap one's hands or shout after performances to indicate approvalbless, sign - make the sign of the cross over someone in order to call on God for protection; consecratenod - express or signify by nodding; "He nodded his approval"cross oneself - make the sign of the cross; in the Catholic religionbow, bow down - bend one's knee or body, or lower one's head; "He bowed before the King"; "She bowed her head in shame"shake - shake (a body part) to communicate a greeting, feeling, or cognitive state; "shake one's head"; "She shook her finger at the naughty students"; "The old enemies shook hands"; "Don't shake your fist at me!"beckon, wave - signal with the hands or nod; "She waved to her friends"; "He waved his hand hospitably"

motion

noun1. movement, action, mobility, passing, travel, progress, flow, passage, locomotion, motility, kinesics the laws governing light, sound and motion2. gesture, sign, wave, signal, gesticulation He made a neat chopping motion with his hand.3. proposal, suggestion, recommendation, proposition, submission The conference is now debating the motion.verb1. gesture, direct, wave, signal, nod, beckon, gesticulate She motioned for the doors to be opened.in motion2. in progress, going on, under way, afoot, on the go (informal) His job begins in earnest now that the World Cup is in motion.3. moving, going, working, travelling, functioning, under way, operational, on the move (informal) Always stay seated while a bus is in motion.set or put something in motion start, begin, launch, institute, initiate, activate, spark off, trigger off Her sharp comments set in motion the events that led to her downfall.Related words
adjective kinetic
like kinesomania
fear kinesophobia

motion

noun1. The act or process of moving:move, movement, stir.2. An expressive, meaningful bodily movement:gesticulation, gesture, indication, sign, signal.Informal: high sign.verbTo make bodily motions so as to convey an idea or complement speech:gesticulate, gesture, sign, signal, signalize.Idiom: give the high sign.

Translations

动作动议手势打手势提议

motion

(ˈməuʃən) noun1. the act or state of moving. the motion of the planets; He lost the power of motion.运动2. a single movement or gesture. He summoned the waiter with a motion of the hand. 动作，手势 3. a proposal put before a meeting. She was asked to speak against the motion in the debate. 提议，动议 verb to make a movement or sign eg directing a person or telling him to do something. He motioned (to) her to come nearer. 移动，打手势 ˈmotionless adjective not moving. a motionless figure.不动的motion picture a cinema film. 电影in motion moving. Don't jump on the bus while it is in motion.在运动中

Motion

motion,

the change of position of one body with respect to another. The rate of change is the speedspeed,
change in distance with respect to time. Speed is a scalar rather than a vector quantity; i.e., the speed of a body tells one how fast the body is moving but not the direction of the motion.
..... Click the link for more information. of the body. If the direction of motion is also given, then the velocityvelocity,
change in displacement with respect to time. Displacement is the vector counterpart of distance, having both magnitude and direction. Velocity is therefore also a vector quantity. The magnitude of velocity is known as the speed of a body.
..... Click the link for more information. of the body is determined; velocity is a vectorvector,
quantity having both magnitude and direction; it may be represented by a directed line segment. Many physical quantities are vectors, e.g., force, velocity, and momentum.
..... Click the link for more information. quantity, having both magnitude and direction, while speed is a scalar quantity, having only magnitude.

Types of Motion

Uniform motion is motion at a constant speed in a straight line. Uniform motion can be described by a few simple equations. The distance s covered by a body moving with velocity v during a time t is given by s=vt. If the velocity is changing, either in direction or magnitude, it is called accelerated motion (see accelerationacceleration,
change in the velocity of a body with respect to time. Since velocity is a vector quantity, involving both magnitude and direction, acceleration is also a vector. In order to produce an acceleration, a force must be applied to the body.
..... Click the link for more information. ). Uniformly accelerated motion is motion during which the acceleration remains constant. The average velocity during this time is one half the sum of the initial and final velocities. If a is the acceleration, v_o the original velocity, and v_f the final velocity, then the final velocity is given by v_f=v_o + at. The distance covered during this time is s=v_ot + 1-2 at². In the simplest circular motion the speed is constant but the direction of motion is changing continuously. The acceleration causing this change, known as centripetal acceleration because it is always directed toward the center of the circular path, is given by a=v²/r, where v is the speed and r is the radius of the circle.

The Laws of Motion and Relativity

The relationship between forceforce,
commonly, a "push" or "pull," more properly defined in physics as a quantity that changes the motion, size, or shape of a body. Force is a vector quantity, having both magnitude and direction.
..... Click the link for more information. and motion was expressed by Sir Isaac NewtonNewton, Sir Isaac,
1642–1727, English mathematician and natural philosopher (physicist), who is considered by many the greatest scientist that ever lived. Early Life and Work
..... Click the link for more information. in his three laws of motion: (1) a body at rest tends to remain at rest or a body in motion tends to remain in motion at a constant speed in a straight line unless acted on by an outside force, i.e., if the net unbalanced force is zero, then the acceleration is zero; (2) the acceleration a of a mass m by an unbalanced force F is directly proportional to the force and inversely proportional to the mass, or a = F/m; (3) for every action there is an equal and opposite reaction. The third law implies that the total momentum of a system of bodies not acted on by an external force remains constant (see conservation lawsconservation laws,
in physics, basic laws that together determine which processes can or cannot occur in nature; each law maintains that the total value of the quantity governed by that law, e.g., mass or energy, remains unchanged during physical processes.
..... Click the link for more information. , in physics). Newton's laws of motion, together with his law of gravitationgravitation,
the attractive force existing between any two particles of matter. The Law of Universal Gravitation

Since the gravitational force is experienced by all matter in the universe, from the largest galaxies down to the smallest particles, it is often called
..... Click the link for more information. , provide a satisfactory basis for the explanation of motion of everyday macroscopic objects under everyday conditions. However, when applied to extremely high speeds or extremely small objects, Newton's laws break down.

Motion at speeds approaching the speed of lightlight,
visible electromagnetic radiation. Of the entire electromagnetic spectrum, the human eye is sensitive to only a tiny part, the part that is called light. The wavelengths of visible light range from about 350 or 400 nm to about 750 or 800 nm.
..... Click the link for more information. must be described by the theory of relativityrelativity,
physical theory, introduced by Albert Einstein, that discards the concept of absolute motion and instead treats only relative motion between two systems or frames of reference.
..... Click the link for more information. . The equations derived from the theory of relativity reduce to Newton's when the speed of the object being described is very small compared to that of light. When the motions of extremely small objects (atoms and elementary particleselementary particles,
the most basic physical constituents of the universe. Basic Constituents of Matter

Molecules are built up from the atom, which is the basic unit of any chemical element. The atom in turn is made from the proton, neutron, and electron.
..... Click the link for more information. ) are described, the wavelike properties of matter must be taken into account (see quantum theoryquantum theory,
modern physical theory concerned with the emission and absorption of energy by matter and with the motion of material particles; the quantum theory and the theory of relativity together form the theoretical basis of modern physics.
..... Click the link for more information. ). The theory of relativity also resolves the question of absolute motion. When one speaks of an object as being in motion, such motion is usually in reference to another object which is considered at rest. Although a person sitting in a car is at rest with respect to the car, both in motion with respect to the earth, and the earth is in motion with respect to the sun and the center of the galaxy. All these motions are relative.

It was once thought that there existed a light-carrying medium, known as the luminiferous etherether
or aether,
in physics and astronomy, a hypothetical medium for transmitting light and heat (radiation), filling all unoccupied space; it is also called luminiferous ether. In Newtonian physics all waves are propagated through a medium, e.g.
..... Click the link for more information. , which was in a state of absolute rest. Any object in motion with respect to this hypothetical frame of reference would be in absolute motion. The theory of relativity showed, however, that no such medium was necessary and that all motion could be treated as relative.

Bibliography

See J. C. Maxwell, Matter and Motion (1877, repr. 1952).

Motion

If the position of a material system as measured by a particular observer changes with respect to time, that system is said to be in motion with respect to the observer. Absolute motion, then, has no significance, and only relative motion may be defined; what one observer measures to be at rest, another observer in a different frame of reference may regard as being in motion. See Frame of reference, Relative motion

The time derivatives of the various coordinates used to specify the system may be used to prescribe the motion at any instant of time. How the motion develops in subsequent instants is then determined by the laws of motion. In classical dynamics it is supposed that in principle the motion and configuration of the system may be specified to an arbitrary precision, although in quantum mechanics it is recognized that the measurement of the one disturbs the other.

The most general theory of motion that has yet been developed is quantum field theory, which combines both quantum mechanics and relativity theory, as well as the experimentally observed fact that elementary particles can be created and annihilated. See Degree of freedom (mechanics), Dynamics, Hamilton's equations of motion, Harmonic motion, Kinematics, Kinetics (classical mechanics), Lagrange's equations, Newton's laws of motion, Oscillation, Periodic motion, Quantum field theory, Quantum mechanics, Rectilinear motion, Relativity, Rotational motion

Motion

in geometry, a transformation of space that preserves the properties of a figure (dimensions, shape, and so forth). The concept of a motion was formulated as an abstraction of actual motions of rigid bodies.

A motion of Euclidean space is a geometric transformation that preserves the distance between points. It is called proper or improper depending on whether it preserves or changes orientation. Apart from a translation, a motion is an orthogonal transformation.

A proper motion in a plane can be specified relative to a rectangular system of coordinates (x, y) by the formulas

x̄ = x cos φ - y sin φ + a
ȳ = y sin φ + y cos φ + b

that show that the set of all proper motions in a plane depends on the three parameters a, b, and φ. By assigning particular values to a and b we determine a translation of the plane by the vector (a, b), and by assigning a particular value to φ we determine a rotation of the plane about the origin by the angle φ. A proper motion can be represented as a translation or as a rotation about some point. An improper motion can be represented as a reflection in a line or as a product (the result of successive application) of a translation in some direction and a reflection in a line having the same direction.

A proper motion in space can be represented as a rotation about an axis, or a translation, or a screw motion (a rotation about an axis followed by a translation in the direction of this axis). An improper motion in space can be represented as a reflection in a plane, or a product of a reflection in a plane and a rotation about an axis perpendicular to this plane, or a product of a reflection in a plane and a translation determined by a vector parallel to this plane.

Apart from a translation, a motion in space can be represented analytically by a linear transformation with an orthogonal matrix having a determinant equal to 1 or -1 depending on whether the motion is proper or improper.

The concept of a motion is carried over into Riemannian spaces and spaces of affine connection. The concept of a motion plays an important role in the Riemannian spaces associated with the theory of relativity (the strong asymmetry of gravitational fields imposes restrictions on the motion of rigid bodies in such spaces).

Motion may be used as an undefined term in the axiomatic development of geometry. In this case, the axioms of a motion are substituted for the axioms of congruence. The congruence of segments, angles, and other figures is then defined in terms of motions (two figures are said to be congruent if there exists a motion that carries one figure into the other). The totality of motions forms a group.

REFERENCES

Adamar, J. Elemenlarnaia geometriia.Part 1, 3rd ed., Moscow, 1948; part 2, 2nd ed., Moscow, 1951. (Translated from French.)
Rashevskii, P. K. Rimanova geometriia i tenzornyi analiz,3rd ed. Moscow, 1967.
Aleksandrov, P. S. Lektsii po analiticheskoi geometrii.Moscow, 1968.

E. G. POZNIAK

Motion

a mode of matter’s existence and its most important attribute. In its most general aspect motion is “change in general” (F. Engels, in K. Marx and F. Engels, Soch.,2nd ed., vol. 20, p. 563), any kind of interaction between material objects.

The concept of the universality of motion originated in remote antiquity among the thinkers of China, India, and Greece. The ancient Greek philosophers, including the Milesian school, Heraclitus, Democritus, and Epicurus, regarded the primal principles of all things—water, apeiron, air, fire, and atoms—as being in a state of constant motion and change. Aristotle believed that an “ignorance of motion of necessity means an ignorance of nature” (Physics,III 1, 200 b; Russian translation, Moscow, 1936). The conception of motion as a mode of matter’s existence was precisely formulated in the 18th century by the British philosopher J. Toland and subsequently by the French materialist P. Holbach. However, they conceived of motion itself as being merely mechanical displacement and interaction. Profound ideas concerning the interpretation of motion were expressed by the objective idealists G. W. Leibniz, G. Hegel, and others. Thus, Hegel transcends the conception of motion as merely mechanical displacement and formulates general laws of motion—the law of the transition from quantitative changes to qualitative ones, the law of the conflict of opposites, and the law of the negation of the negation.

A new and higher stage in the understanding of motion as a mode of matter’s being was attained with the creation of dialectical materialism by K. Marx and F. Engels. This doctrine concerning motion was further developed during the 20th century in the works of V. I. Lenin. Dialectical materialism has substantiated the link between matter and motion in a new way and has established the principle that matter in motion can be neither created nor destroyed. “Matter without motion is just as inconceivable as motion without matter. Motion, therefore, can no more be created or destroyed than matter itself (F. Engels, in K. Marx and F. Engels, Soch.,2nd ed., vol. 20, p. 59). The principles of the connection between matter and motion and of the inability of moving matter to be destroyed or created acquired a special significance in the light of the great discoveries in the natural sciences of the 19th and 20th centuries. Lenin put forward the principle of the unity of matter and motion in order to counter the attempts of the so-called energeticism school to reduce matter to energy. Lenin emphasized that matter is not something inert, something to which motion “is added,” nor is it the empty “subject,” of the predicate “to move.” Rather, matter is the foundation and universal vehicle of all states of motion and development. “Whether we say the world is moving matter or that the world is material motion makes no difference whatever” (Poln. sobr. soch.,5th ed., vol. 18, p. 286). Dialectical materialism holds that, along with its material quality, the principal characteristics of motion are its absoluteness and its contradictory quality. The motion of matter is absolute, whereas all rest is relative and represents one of the aspects of motion. It determines all the characteristics and manifestations of the surrounding world and the inner content of all objects and phenomena. The contradictory nature of motion consists in the unbroken unity of two opposing factors—changeability and stability, motion and rest. In fact, the concept of change makes sense only in connection with the idea of a relatively stable, continuously fixed state. This very change, however, is at the same time also a fixed state, which continues and maintains itself; that is, it also possesses stability. In this contradictory unity of changeability and stability the leading role is played by changeability, for everything new in the world first appears by means of it, whereas stability and rest merely fix what has been attained through this process.

The motion of matter is diverse in its manifestations and exists in various forms. Classification of the principal forms of motion involves making a distinction between inorganic matter and the biological and social spheres. Motion may occur in an ascending line, advancing from simple forms to more complex ones, from what is lower to what is higher; such motion is called development. Motion may also proceed along a descending line, toward simpler forms; that is, it may be regressive.

Motion occurs in space and time, which, as the theory of relativity has established, are merely relative “aspects” of a single form of matter’s existence, that is, space-time.

REFERENCES

Lenin, V. I. Poln. sobr. soch.,5th ed., vol. 29. (See the subject index.)
Hegel, G. W. F. “Filosofiia prirody.” Soch.,vol. 2. Moscow-Leningrad, 1934.
Sviderskii, V. I. Protivorechivost’ dvizheniia i ee proiavleniia.Leningrad, 1959.
Sviderskii, V. I. Nekotorye voprosy dialektiki izmeneniia i razvitiia.Moscow, 1965.
Meliukhin, S. T. Materiia v ee edinststve, beskonechnosti i razvitii.Moscow, 1966.
Ovchinnikov, N. F. Printsipy sokhraneniia. Moscow, 1966.
Struktura i formy materii. Moscow, 1967. (Collected essays.)

V. I. SVIDERSKII

motion

[′mō·shən] (mechanics) A continuous change of position of a body.

motion

1. the process of continual change in the physical position of an object; movement 2. a movement or action, esp of part of the human body; a gesture 3. a. the capacity for movement b. a manner of movement, esp walking; gait 4. a mental impulse 5. Politics a formal proposal to be discussed and voted on in a debate, meeting, etc. 6. Law an application made to a judge or court for an order or ruling necessary to the conduct of legal proceedings 7. Brita. the evacuation of the bowels b. excrement 8. a. part of a moving mechanism b. the action of such a part 9. Music the upward or downward course followed by a part or melody. Parts whose progressions are in the same direction exhibit similar motion, while two parts whose progressions are in opposite directions exhibit contrary motion

Motion

Andrew. born 1952, British poet and biographer; his collections include Pleasure Steamers (1978) and Public Property (2002): poet laureate from 1999

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Motion

motion,

Types of Motion

The Laws of Motion and Relativity

Bibliography

Motion

Motion

REFERENCES

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REFERENCES

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Patient discussion about motion

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Further readings

Cross-references

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MOTION

motion

Synonyms for motion

noun movement

Synonyms

noun gesture

Synonyms

noun proposal