impetus vs speediness

impetus

noun
  • The force or energy associated with a moving body; a stimulus. 

  • Anything that impels; a stimulating factor. 

  • An activity in response to a stimulus. 

  • A force, either internal or external, that impels; an impulse. 

  • A principle of motive force, held as exquivalent to weight times velocity by John Buridan, in an auxiliary theory of Aristotelian dynamics introduced by John Philoponus, describing projectile motion against gravity as linear until it transitions to a vertical drop and the intellectual precursor to the concepts of inertia, momentum and acceleration in classical mechanics. 

speediness

noun
  • The property of being fast; swiftness. 

How often have the words impetus and speediness occurred in a corpus of books? (source: Google Ngram Viewer )