1. when playing the piano, each key has a specific number of times it vibrates. the number of string vibrations correspond to changing what quality of sound? loudness
pitch
amplitude
range
2. what is the lowest level of sound that can be detected by human hearing?
0 hz
10 hz
20 hz
100 hz
3.

the sound waves used for sonar are
infrasound
ultrasound
audible
4. at close range, a ship's foghorn or the air horn on a truck will probably have a , low, medium) decibel reading.
5. a loud explosion will produce
a high-amplitude sound wave
a low-amplitude sound wave
a sound wave with a single frequency

Hello mate!

1) the number of times that the string vibrates ober the unit of time, is the frequency of the note.

This canges the pitch of the note, where a high frequency is asociated with a high pitch (the first string in the guitar) and a low frequency is asociated with a low pitch (the thickest string on a guitar)

2) Is commonly stated that the human hearing can detect sounds of 20Hz, but in some situations can be detected sounds with lower frequency, where the samallest detected is 12Hz

3) The sound waves used for a sonar can vary from infrasound to ultrasound, depending of the range that the sonar covers, there is no right answer here.

4) A high decibel reading, this is because the source "shots" the sound un a prefered direction, then the intensity of the sound is very high right next to the source.

5) A loud explosion will produce a high-amplitude sound wave, this is because the amplitud is directly relationated with the intensity (or loudnes) of the sound wave.

an obstruction

compass can be used day and night, cloudy or sunny