6

General terms

English


6.1 SCALAR [SCALAR QUANTITY]
Quantity that is specified by one real number.
6.2 VECTOR
1. Directed line segment. 2. Row or column matrix.
6.3 VECTOR QUANTITY
Quantity which in addition to being geometrically represented by a vector also adds in accordance with the parallelogram/triangle rule.
6.4 VECTOR FIELD
Region in which every point has a definite vector associated with it.
6.5 VECTOR FUNCTION
Relationship which determines a vector for every particular value of a scalar parameter.
6.6 GRADIENT
Vector whose components along the axes of a rectangular system of coordinates at a given point are equal to the partial derivatives of a given scalar function of the coordinates.
6.7 POTENTIAL
Scalar function whose gradient is the opposite vector to the vector of a given vector field.
6.8 VELOCITY HODOGRAPH
Locus of the arrowhead of the velocity vectors of a moving point, when all the vectors are drawn from a common origin.
6.9 PEAK VALUE:
Maximum value of a quantity during a given interval. Note: A peak value of an oscillating quantity is usually taken as the maximum deviation of that quantity from the mean value.
6.10 MEAN-SQUARE VALUE
Average of the squared values of a function over a given interval.
6.11 ROOT-MEAN-SQUARE [r.m.s.] VALUE
Square root of the mean-square value.
6.12 TIME HISTORY
Magnitude of a quantity expressed as a function of time.
6.13 TIME CONSTANT [RELAXATION TIME]
Time taken by an exponentially decaying quantity to decrease in magnitude by a factor 1/e=0.3679.
6.14 SIGNAL
Disturbance used to convey information.
6.15 INPUT
Disturbance or signal applied to a system.
6.16 OUTPUT
Response of a system to an input.
6.17 NOISE
Disturbance, generally of a random nature , which is imposed on the output due to effects not considered in the theoretical model
6.18 ACTIVE DEVICE/SYSTEM
Device or system with its own independent source of power.
6.19 PASSIVE DEVICE/SYSTEM
Device whose output energy is supplied entirely through its input.
6.20 GENERALIZED COORDINATE
One of a set of independent variables which determine uniquely the configuration of a system.
6.21 SYSTEM
Entirety of components functioning as a whole.
6.22 TECHNICAL SYSTEM
Practical realisation of a system.
6.23 MODEL
Idealised, usually simplified representation of a system.
6.24 DEVICE
Machine or machine component to perform one or more (simple) tasks.
6.25 PROCESS
Any change of a system and/or its behaviour with respect to time.
6.26 PHYSICAL MODEL
Model in which physical properties are considered.
6.27 SCALE MODEL
Physical model in which similarity laws related to the original are considered
6.28 MATHEMATICAL MODEL
Set of mathematical equations describing the physical properties of a system
6.29 MECHANICAL MODEL
Physical model in which only the mechanical properties are considered.
6.30 DISCRETE MODEL
Model described by a finite number of ordinary (differential) equations
6.31 CONTINUOUS MODEL
Model described by a finite number of partial differential or integral equations
6.32 HYBRID MODEL
Mechanical model consisting of both discrete model and continuous model elements