Yes. By definition, sound is: "mechanical vibrations transmitted through an elastic medium" (dictionary.com). Noise doesn't need to be perceived to be defined as "sound" since it is a mechanical entity.
No, ninjas don't make make sounds anyway, but if it does, it's definitly the last sound you'll ever hear.Only Chuck Norris can know whether or not it makes a sound, and anyways he's the reason why...
No it doesn't make a sound because there was no one to hear it. So we don't know if it really even made a sound. That's the theory because NO ONE HEARD IT!
Of course it makes a sound. This question is not supposed to be a brain teaser or and exam question, it is about nature and the connection between nature and humans. It is implying that "no one"...
some people may say yes and no but the scientific answer is no Yes, it does. It always does--doesn't matter if it is heard or not! Comment to Simplemary's answer: Absolutely correct.