12.2. Longitudinal Waves http://www.ck12.org
Example Problem:A sonar signal (sonar is sound waves traveling through water) of 1. 00 × 106 Hz frequency has
a wavelength of 1.50 mm in water. What is the speed of sound in water?
Solution:v=λf= ( 0 .00150 m)( 1. 00 × 106 s−^1 ) =1500 m/s
Example Problem:A sound wave of wavelength 0.70 m and velocity 330 m/s is produced for 0.50 s.
a. What is the frequency of the wave?
b. How many complete waves are emitted in this time interval?
c. After 0.50 s, how far is the wave front from the source of the sound?Solution:
a. f=vλ=^3300. 70 m/sm =470 s−^1
b. complete waves= (470 cycles/s)( 0 .50 s) =235 cycles
c. distance= (330 m/s)( 0 .50 s) =115 mSummary
- Longitudinal waves cause the particles of medium to move parallel to the direction of the wave.
Practice
Questions
The following video explains how a tuning fork creates sound. Use this resource to answer the questions that follow.