Distance Versus Directed Distance and Displacement
Distance cannot be negative and distance travelled never decreases. Distance is a scalar quantity or a magnitude, whereas displacement is a vector quantity with both magnitude and direction.
The distance covered by a vehicle (for example as recorded by an odometer), person, animal, or object along a curved path from a point A to a point B should be distinguished from the straight line distance from A to B. For example whatever the distance covered during a round trip from A to B and back to A, the displacement is zero as start and end points coincide. In general the straight line distance does not equal distance travelled, except for journeys in a straight line.
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Famous quotes containing the words distance and/or directed:
“And then he heard some old forgotten talk
At a short distance like a hundred miles
Filling the air with its secrecy,
And was afraid of all the living air....”
—Allen Tate (1899–1979)
“Sadism is all right in its place, but it should be directed to proper ends.”
—Sigmund Freud (1856–1939)