Why is $s$ used for arc length? I looked around online, but I can't find a definite answer.
Thank you!
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Sign up to join this communityWhy is $s$ used for arc length? I looked around online, but I can't find a definite answer.
Thank you!
I strongly agree with Karl's and Björn's comments regarding the Latin orgin: spatium.
See: Leonhard Euler, Mechanica sive motus scientia analytice exposita, Tomus I, Petropoli, 1736 :
Propositio 4 [ page 13 ] Sit spatium $AM$, sive sit linea recta sive curva, $=s$, et celeritas, quam corpus habet in M sit $c$, quae erit functio quaedam ipsius $s$. Ab $M$ accipiatur elementum $Mm$, quod igitur motu aequabili idque celeritate $c$ percurri concipiendum est. Vocato elemento $Mm$, $ds$; erit tempus quo hoc elementum pe[r]curritur $=\frac{ds}{c}$. Integrando ergo habebitur tempus, quo totus arcus $AM$ absolvitur $=\int\frac{ds}{c}$.