1) What frequency of sound traveling in air at 20C has a wavelength equal to 1.8 m, the average height of a person?

2) A 400-Hz sound travels through pure neon. The wavelength of the sound is measured to be 1.09 m. What is the speed of sound in neon?

3) The force stretching the D string on a certain guitar is 155 N. The string's linear mass density is 0.007 kg/m. What is the speed of waves on the string?

4)Approximately how many times louder is a 145-dB sound than a 75-dB sound?