Sound Waves
The distance between a point on one cycle of a wave and the same point on the next cycle.
What is wavelength?
A wave in which the medium vibrates at right angles to the direction of the wave.
What is a transverse wave?
Sound waves oscillate parallel or perpendicular to the direction in which the wave travels.
What is a parallel?
A recorder is a woodwind instrument in which the player blows into a tube, setting up a wave in the tube. A musician has 2 recorders. The first one is rather short, and the second one is significantly longer. Which recorder is capable of playing notes with the lowest pitch?
What is the longer recorder?
During a thunderstorm, the temperature is 10 degrees C. If you see a lightning strike and then hear the thunder 2.0 seconds later, how far away did the lightning strike?
T = 10 degrees C
t = 2.0 sec
v = (331.5 + 0.6t) m/s
= (331.5 + 0.6(2.0)) m/s
v = 337.5 m/s
d = vt = (337.5 m/s) (2.0 s) = 675 m
An indication of how high or low a sound is, which is primarily determined by the frequency of the sound wave
What is pitch?
A wave that travels along the surface of a medium.
What is a surface wave?
For waves moving at a constant speed, if wavelength is doubled, what happens to the frequency?
What is frequency is halved?
In a longitudinal wave, areas where the particles of the medium are pulled farther apart.
What are rarefactions?
Mechanical waves need a ______________ to travel through.
What is a medium.
The number of complete cycles in a given time.
What is frequency?
The maximum displacement of the medium from its rest position
What is amplitude?
Which of the following sound waves have the longest wavelength?
a. Sonic waves
b. Infrasonic waves
c. Surface waves
d. Ultrasonic waves
What is infrasonic waves?
A sound wave can not travel through outer space because of the lack of .
What is matter.
An amplifier takes a 30 dB sound and turns it into an 80 dB sound. How many times larger is the intensity of the sound waves coming out of the amplifier as compared to the intensity of the sound waves going into the amplifier?
80 dB - 30 dB = 50 dB
Since each 10 dB represents a 10-fold increase in sound wave intensity, we need to determine how many factors of 10 we need by dividing 50 by 10, which is 5. Then you multiply 10 by itself 5 times.
10x10x10x10x10 = 100,000
A disturbance in matter that transfers energy through the matter
What is a mechanical wave?
A wave in which the vibration of the medium is parallel to the direction the wave travels.
What is a longitudinal wave?
? = wavelength x frequency
What is speed?
What are compressions?
T = 17 degrees C
wavelength = 2 m
v = (331.5 + 0.6t)m/s = (331.5 + 0.6(17))
v = 341.7 m/s
f = speed/wavelength = 341.7/2 = 170.85 Hz
Any speed that is faster than the speed of sound in the medium of interest.
What is supersonic sound?
A change in sound frequency caused by the motion of the sound source, motion of the listener, or both.
What is the Doppler effect?
Sound waves are _______ waves.
What is longitudinal?
The more energy a wave has, the greater the ___________.
What is amplitude?
A jet travels through 10 degrees C air at Mach 3. What is its speed in meters per second?
T = 10 degrees C
Mach = 3
v = ?
v = (331.5 + 0.6T) = (331.5 + 0.6(10))
v = 337.5 m/s
Multiply by 3 for Mach 3
v = 3(337.5 m/s) = 1012.5 m/s