The term escape velocity is quite common to us. But we know velocity is a dimension dependent on the direction. But the escape velocity has same value irrespective of from where it is thrown from the earth. So its just the magnitude that matters, not the direction. In that sense it should be given the name as escape speed. But it is not given so, can anyone explain?
Answer
As others have said, escape velocity is a speed, not a velocity. As to why, see the etymology of the word velocity:
early 15c., from Latin velocitatem (nominative velocitas) "swiftness, speed," from velox (genitive velocis) "swift, speedy, rapid, quick," of uncertain origin.
Velocity used to mean speed, and we still say things like "high velocity bullet". The vector-quantity meaning came later. Interestingly, when you look at translations of Einstein's papers such as here, you see the word velocity used instead of the word speed. Then when you backtrack to the original German, you find the original word was Geschwindigkeit. Native German speakers have advised me that it means both speed and velocity.
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