On page 462 in the chapter summary (aka «glossary») for chapter 17 it is unconventional and unhelpful to define sound as limited to the human-audible frequency range. The dictionary defines ultrasound as a form of sound. Cats can hear sounds up to 70 kHz or thereabouts.
This is a physics book, after all. The physics of sound is the same, whether or not it is directly perceptible to humans.
On page 462 in the chapter summary (aka «glossary») for chapter 17 it is unconventional and unhelpful to define
soundas limited to the human-audible frequency range. The dictionary defines ultrasound as a form of sound. Cats can hear sounds up to 70 kHz or thereabouts.This is a physics book, after all. The physics of sound is the same, whether or not it is directly perceptible to humans.
Suggestion
An decent attempt to define sound can be found at https://www.av8n.com/physics/wave-intro.htm#wave-ex-sound