PhysicalQuantity

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Physical quantities.

Entity["PhysicalQuantity",name] or

represents an entity of type "PhysicalQuantity".

[prop]

gives the value of a specified property.

[{propi,}]

gives the value of a list of properties.

EntityClass["PhysicalQuantity",{propispeci,}]

represents a class of entities with values of propi defined by speci.

Sample Entities

Sample Entity Classes

Properties

  • Abbreviationsabbreviations
    AlgebraicTypesalgebraic types
    AlternateNamesalternate names
    BasePhysicalQuantitybase physical quantity
    CanonicalUnitcanonical unit
    Classesclasses
    Dimensionsdimensions
    EntityClassesentity classes
    Instancesinstances
    Namename
    NamedSIUnitnamed SI unit
    PhysicalPropertyTypephysical property type
    QuantityVariablequantity variable
    SIBaseUnitSI base unit
    SIUnitSI unit
    StandardIdentifiersstandard identifiers
    StandardSymbolsstandard symbols
    Symbolssymbols

Details

  • "PhysicalQuantity" entities include named physical properties that can be quantified by measurement, including length, mass, time, speed, force, etc.
  • "PhysicalQuantity" entity classes include groups of physical quantities that count entities, are instances of a more general quantity, are base quantities in the SI system of units, etc.
  • Some properties are available for the "PhysicalQuantity" entity type as a whole and can be given using the form EntityValue["PhysicalQuantity",property ]. Such properties include:
  • "Properties"the list of available properties
    "PropertyCanonicalNames"the standard names of available properties
    "SampleEntities"a sample list of available entities (typically of length 10)
    "SampleEntityClasses"a sample list of available entity classes (typically of length 10)
    "EntityCount"number of entities available
    "Entities"the list of available entities
    "EntityCanonicalNames"the standard names of available entities
    "EntityClasses"the list of available entity classes
    "EntityClassCanonicalNames"the standard names of available entity classes
    "PropertyClasses"the list of available property classes
    "PropertyClassCanonicalNames"the standard names of available property classes
    "PropertyCount"number of properties available
  • The following annotations can be used in the third argument of EntityValue["PhysicalQuantity",property,annotation]:
  • "Source"source information for the property
    "Date"the date associated with the entity-property value (if any)
    "EntityAssociation"an association of entities and entity-property values
    "PropertyAssociation"an association of properties and entity-property values
    "EntityPropertyAssociation"an association in which the specified entities are keys, and values are a nested association of properties and entity-property values
    "PropertyEntityAssociation"an association in which the specified properties are keys, and values are a nested association of entities and entity-property values
    "Dataset"a dataset in which the specified entities are keys, and values are an association of property names and entity-property values
  • The following annotations can be used in the second argument of EntityValue[property,annotation]:
  • "Qualifiers"the list of possible qualifiers for the property
    "QualifierValues"the list of possible values that can be given to each qualifier
    "DefaultQualifierValues"the list of default values for the property's qualifiers
    "Description"a brief textual description of the property
    "Definition"a detailed textual definition of the property
    "PhysicalQuantity"the physical quantity associated with the entity-property value
    "Unit"the unit associated with the entity-property value
  • A qualifier value of Automatic indicates that an applicable format of values can be used; e.g. for the "Date" qualifier, this includes a proper date or date span.

Examples

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Basic Examples  (4)

Find a property value for an entity:

Retrieve a dataset of all available properties for an entity:

Retrieve SI base physical quantities:

Return physical quantity entities that are instances of length:

Scope  (1)

Implicit Entity Classes  (1)

Retrieve physical quantities with dimensions of [mass]/[time]:

Applications  (3)

Physical quantity entities can be used with QuantityVariable:

Physical quantity entities can be used with QuantityVariableCanonicalUnit:

Compare with the corresponding physical quantity property:

Physical quantity entities can be used with QuantityVariableDimensions:

Compare with the corresponding physical quantity property:

Create a crosswalk to Wikidata identifiers:

Relations to Other Entity Types  (2)

Use FromEntity to convert from a physical quantity entity to a quantity variable:

Use ToEntity to convert a quantity variable to a physical quantity entity:

Neat Examples  (2)

View the number of physical quantities by total absolute dimension:

Plot the physical quantities with greatest absolute total dimensions:

Visualize the dimensionality of physical quantities based on the standard dimensions:

Collect all physical quantities containing only those dimensions:

Convert dimension lists to vectors:

Visualize as a feature space plot: