Translation:The speed of light is much faster than that of sound.
I think this article says yes (too bad it's over my head): http://elcastellano.elnortedecastilla.es/castellano/aula/mucho-m%C3%A1s-mucho-menos-mucho-mayor-mucho-menor and this one has examples: http://www.linguee.com/spanish-english/translation/mucho+menor.html
It's mucho. I know this link is in Spanish, but all you have to read is the last paragraph, and it is short: http://elcastellano.elnortedecastilla.es/castellano/aula/mucho-m%C3%A1s-mucho-menos-mucho-mayor-mucho-menor
Every area of study has its special words, and those words will be translated in a way known only to bilingual people in the field. So yes, there will different words or phrases for what you are asking about in physics texts, but I don't know them. To me, speed and velocity are both velocidad.
Thanks :). So Spanish DOES make the distinction. Still though, I wonder if Spanish people bother to be technically correct. I have heard a fair share of English speaking people misuse the term "velocity" here in Canada.
I don't know if I should report this to DL. DL often likes to make the argument that "if everyone uses it then it is ok". I personally think that is a fallacious argument and could possibly lead to loss of the meaning of a word... But I do not control language evolution! lol
Rapidez = speed (rapidity), also celeridad= speed.
Velocidad = velocity.
Funny enough the wikipedia page for velocity in my native language (فارسی) calls velocity as "vectoral speed", and it calls speed as... you guessed it... "speed".