Flashcards in Chapter 7- Waves And Sound Deck (24)
What type of wave is sound?
Like people doing the wave in a stadium. Each person being a particle moving up and down (perpendicular)
Ex: electromagnetic waves
Transverse wave and energy
Particles oscillating perpendicular to the direction of energy transfer
Longitudinal waves and energy
Particles oscillate parallel to direction of energy transfer
Ex: sound waves
Speed of wave
v = f(wavelength)
Period of wave
T = 1/f
Used in simple harmonic motion in springs and pendula
w= 2(pi)f = 2(pi)/T
Quality of sound. Determined by natural frequency of the object
Between 20 and 20,000 Hz
2 types of waves
Speed of sound
Detector / source
Pressure / Area
B = 10 log(I/I*)
I*- 1 x 10^-12
Effects of dampening / attenuation
Same frequency (pitch), gradual loss of sound (smaller amplitude)
Wavelength of standing wave
n- number of half-wavelengths supported by the string
f = nv/2L
First harmonic. Lowest frequency (longest wavelength) of a standing wave that can be supported in a given string.
For strings attached at both ends how do you know which harmonic it is?
Number of antinodes
For open pipes how can you tell which harmonic it is?
Number of nodes present
Closed pipe equation for wavelength
n- odd numbers only, quarter wavelengths
Frequency of standing wave in a closed pipe
Ultrasound machines calculate distance based on...
Travel time of the reflected sound