The act, process, or instance of change of position. Absolute motion is motion relative to a fixed point. Actual motion is motion of an object relative to the earth. Apparent or relative motion is change of position as observed from a reference point which may itself be in motion. Diurnal motion is the apparent daily motion of a celestial body. Direct motion is the apparent motion of a planet eastward among the stars; retrograde motion, the apparent motion westward among the stars. Motion of a celestial body through space is called space motion, which is composed of two components: proper motion, that component perpendicular to the line of sight; and radial motion, that component in the direction of the line of sight. Also called MOVEMENT, especially when used in connection with problems involving the motion of one vessel relative to another.
Related Terms |
RESTRICTOR
A device for producing a deliberate pressure drop or resistance in a line by reducing the cross-sectional flow area.
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AFT
Back of the vessel.
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ASTERN
A backward movement of a vessel
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ATHWARTSHIP
Across the ship, at right angles to the fore-and-aft centerline
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UPBOUND
A vessel traveling upstream.
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BEAM
The width of a ship. Also called breadth.
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BREADTH
The width of a ship.
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AFFREIGHTMENT
A hiring of a vessel
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CATAMARAN
A double hulled vessel
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COLLIER
Vessel used for transporting coal.
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