Sound and Doppler Effect Flashcards
What is the speed of sound through air?
340 m/s
Compare the velocity of sound in solids, liquids, gases.
Vsolid > v liquid > v gas
Explain how sound works
Sound waves arise from longitudinal collisions between molecules around it. The more likely the molecules collide, then the more likely sound will be produced.
Relate molecular weight and speed of molecules
The heavier the molecule, then the slower it will travel.
Relate intermolecular forces and speed of molecules
The greater the intermolecular forces, then it will move faster to it’s normal position.
What range can humans process sound?
20 to 20,000 Hz.
Relate pitch and frequency
The higher the pitch, the higher the frequency.
The lower the pitch, the lower the frequency.
What is intensity?
Intensity is related to how loud the sound is. Intensity is related the the amplitude of the wave. Large amplitude means, high intensity, and more loud.
Equation for Intensity
Power / Area. Watts/ meters squared.
What is the intensity reference
10^-12 to 1 w/m^2
What is the shortcut for decibels
dB+10= 10(I)
What is the formula for the doppler effect?
FL = FS ( V+/-VL) / (V+/- VS)
Relate frequency and relative motion.
Frequency increases as the objects get close.
Frequency decreases as the objects go away.
Contrast nodes and antinodes
Nodes don’t move
Antimodes have movement.
What is the equation for frequency and wavelength for standing waves?
Frequency is: nv/ 2L
Wavelength is: 2L / n
velocity just depends on the type of string.
How do you calculate the fundamental frequency ?
Subtract two consecutive harmonics.
How do you calculate beat frequency?
Subtract two beats. Take the absolute value.
What is the equation for frequency and wavelength for open pipes?
L = wavelength/ 2 frequency = v/ 2L
What is the equation for frequency and wavelength for closed pipe?
Frequency = nv/ 4L
Most important equation for waves
velocity = frequency (wavelength)
Describe speed of gases in different types of temperatures.
Speed of gases travels faster in warmer conditions.
Relate wavelength, frequency, and changing mediums
When sound goes from one medium to another, the frequency stays the same however the velocity and the wavelength change.
Relate velocity and sound wave frequency when traveling through a medium.
The velocity in a give medium is always the same regardless of the frequency.
What is the formula for intensity of a sound wave?
Intensity is power / area. Area is 4 PI r^4
Relate objects moving in the same direction with frequency
Objects moving in the same direction and speed the frequency cancels out.
