A teacher wants to demonstrate that the speed of sound is not a constant valuConsidering her regular classroom voice as the control, which of the following will increase the speed of sound leaving her mouth? (a) Submerge her mouth underwater and speak at the same volume.
(b) Increase the temperature of the room and speak at the same volume.
(c) Increase the pitch of her voice and speak at the same volume. (a) I only
(b) I and II only
(c) I, II and III
(d) II and III
(e) III only

Video Transcript

This is College Physics Answers with Shaun Dychko. This teacher wants to increase the speed of sound leaving from her mouth and she can do that using technique one, submerge her mouth underwater because water is more dense than air and a denser media will transmit sound more quickly. And she can also increase the temperature of the room because we know the speed of sound in air for example is 331 meters per second times the square root of the absolute temperature over 273. So we have a formula showing us that and so as T increases, so does the wave speed. So two will also work. Three does not work because pitch does not affect the speed of the wave. So, the answer is b, one and two only.