Moment d'un vecteur

Résumé

Le moment d'un vecteur peut se définir par rapport à un point ou par rapport à un axe orienté. Le moment par rapport à un point est un vecteur, le moment par rapport à un axe est un scalaire. Les moments d'un vecteur vrai (ou vecteur polaire) sont des pseudovecteurs ou des pseudoscalaires, ceux d'un pseudovecteur sont des vecteurs vrais ou des scalaires vrais. Définitions

Le moment d'un vecteur vrai (ou vecteur polaire) \vec V (de position M) par rapport à un point O est un pseudovecteur (ou vecteur axial) défini par le produit vectoriel : *:\overset\hookrightarrow{M_\mathrm O}(\vec V)=\overrightarrow\mathrm{OM}\wedge\vec V.
Le moment d'un vecteur vrai \vec V (de position M) par rapport à un axe orienté Δ (de vecteur unitaire \hat u) est un pseudoscalaire défini comme la projection de \overset\hookrightarrow{M_\mathrm O}(\vec V) sur l'axe, où O est un point quelconque de l'axe : *:M_\Delta(\vec V)=\h

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