Final answer:
Turning the tuning pegs of a guitar to adjust the string tension changes the pitch of the sound by altering the frequency of the sound waves produced by the string. Increasing tension raises the pitch, while decreasing tension lowers it. The volume is affected by the amplitude of the vibrations.
Step-by-step explanation:
When a guitar string is plucked and the tuning peg is turned, adjusting the tension on the string, the pitch of the sound produced by the guitar changes. As the tension increases, the speed of the waves in the string increases, leading to a higher frequency of sound, and thus a higher pitch. Conversely, decreasing the tension will slow down the waves in the string, resulting in a lower frequency of sound, and thereby a lower pitch.
The linear density and tension of the string are directly responsible for the speed of the waves in the string. Therefore, by using the tuning pegs to adjust string tension, a guitarist can control the frequency of the sound waves produced.
Additionally, the period of the oscillations will stay constant for a given string under constant tension, and the amplitude of the vibrations affects the volume, not the pitch.