When one plays a guitar, it is so important to remember all the physics behind it. Waves have a lot to do with the sound we hear from them. For example, without a large amplitude, it would not be heard. And when one changes notes, it changes the frequency that is heard. Because the wave is longitudinal, it needs a medium to travel through which is why in a vacuum you would not be able to hear someome playing. The pulses vibrate parallel to the wave because in a longitudinal wave thats their path.
Also, playing the guitar has a lot to do with mechanical energy as one strums the strings. Without the physical motion of the player, there would be no sound. Overtones are a cool thing string instruments have that have a lot to di with waves, which is another physics point!
Next time one picks up a guitar remember all the physics behind it!!!