An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 3 Search : unstable
unstable
  ناپایدار   
nâpâydâr (#)

Fr.: instable   

Not → stable, as in → unstable atom, → unstable equilibrium.

un-; → stable.

unstable atom
  اتم ِ ناپایدار   
atom-e nâpâydâr (#)

Fr.: atome instable   

An atom whose nuclei → decay by → radioactivity.

unstable; → atom.

unstable equilibrium
  ترازمندی ِ ناپایدار   
tarâzmandi-ye nâpâydâr

Fr.: équilibre instable   

An equilibrium state of a system in which if a small perturbation away from equilibrium is applied, the system will move farther away from equilibrium state. For example, mechanical equilibrium in which the potential energy is a maximum, as a sphere placed on top of a hill. Mathematically, if the second derivative of the energy with respect to the coordinate of interest is negative, the system is in an unstable equilibrium. → stable equilibrium.

unstable; → equilibrium.