CENTRIPETAL FORCE • FREE-TRANSLATOR.COM • Definition of Centripetal force

... extend its influence out into the depths of space, so as to include, for example, the moon. Obviously some force pulls the moon constantly towards the earth; otherwise that body would fly off at a tangent and never return. May not this so-called centripetal force be identical with terrestrial gravitation? Such was Newton's query. Probably many another man since Anaxagoras had asked the same question, but assuredly Newton was the first man to find ...

— A History of Science, Volume 2(of 5) • Henry Smith Williams