SOUND
S.H.M.
MORE SOUND
WAVES
MORE WAVES
100
What kind of wave is sound?
LONGITUDINAL or Compression wave
100
What are the two examples of SHM we worked with in class?
spring mass pendulum
100
What kinds of waves do we see in pipes?
Standing waves http://www.phys.unsw.edu.au/jw/graphics/openclosed.gif
100
What is the variable used to describe the point of maximum displacement from equilibrium?
A - Amplitude
100
What is the wave equation?
v = frequency * wavelength v= f * lambda
200
When a bell is stuck it creates regions of high and low_________________.
Pressure http://www.bing.com/images/search?q=sound+waves+from+a+bell&view=detail&id=7DA03990B2C1206F819C29368124EDB16E08503F&first=0&FORM=IDFRIR
200
What is the name of the wave (graph) we see if we were to trace the motion of a mass on a spring?
Sine (or Cosine)
200
What is the variable that corresponds to pitch?
Frequency (f)
200
SEE DIAGRAM. What is the period of this wave?
4 sec
200
What is the frequency of this wave?
0.25 Hz
300
On a closed pipe, how many wavelengths are in the fundamental frequency
1/4 (lamda over four) http://images.tutorvista.com/content/waves/closed-pipe-vibration-modes.gif
300
In a siple pendulum: What affects the period the most? Length, mass or amplitude of the oscillations?
Length- see the formula
300
Sound waves move slower at these temperatures.
What are low temperatures?
300
What are the two kinds of waves?
Transverse and Longitudinal
300
What happens to the velocity, frequency and wavelength when a wave traveling through a rope is transfered to a thicker/denser rope?
Frequency remains the same. velocity and wavelength are diminished
400
In terms of the features of a sound (pressure) standing wave, what is the diference between an open pipe and a closed pipe instrument?
In a closed pipe you will see a pressure node at one end and an antinode at the oposite. In an open pipe you will see nodes at both ends. See page 413 http://www.mrfizix.com/home/sound_files/image066.jpg
400
This is the signature equation for SHM.
What is is F= - ( &) x Where & is any constant. For a pendulum & is gravity "g" For a spring mass sytem & is the spring constant "k"
400
These are the tree parameters a guitar player can control to affect the pitch of a guitar string.
What are Length, tension and density? f = v/(2L) v= squareroot(T/mu) Notice that the velocity of the wave is only affected by the tension of the string and the medium it's made out of. In general the velocity of a wave is dependant on the medium it travels in.
400
What is the wavelenght of this wave? see diagram
24m
400
This is what happens to the frequency, velocity, wavelenth and amplitude of a wave when it is reflected.
What is everything remains the same, but the amplitude changes signs/ http://w3.shorecrest.org/~Lisa_Peck/Physics/syllabus/soundlight/ch25waves/ch25wave_images/reflectedwaves.jpg
500
Describe resonant frequency
At resonance the applied frequency matches the natural frequency of the object. can you think of some examples of this you have seen in class?
500
A simple pendulum has a period of 2 seconds on earth. What is the length of the string? In order to have the same period, how long would the string have to be on the moon where the acceleration due to gravity is 1.6 m/s^2?
The length is .99m On the moon the length would be .16m (16cm)
500
Two instruments are played and a beat frequency of 5 Hz is heard. One of the instruments is playing a frequency of 440Hz, what are the two possible values of the frequency of the other instrument?
Beat f = absolute value (f1-f2) so the first possible frequency is 5Hz = 440Hz + f2 , so f2 = 335 Hz (absolute value) The second possible frequency 5Hz = 440Hz - f2, so f2= 445 (absolute value)
500
You are standing in a canyon and yell out "I LOVE PHYSICS", you hear your echo 3 seconds later. How far away is the canyon wall? assume it's 20 C outside so the velocity of sound = 343m/s
514.5 m
500
In terms of propagation and oscillation: What is the difference between longitudinal and transverse waves? Give an example of each of these What are the graphs of each in terms of displacement as a function of time?
In a longitudinal wave the direction of propagation is the same as the direction of oscillation. In a transverse wave the direction of propagation is perpendicular to the direction os oscillation. Sound is a longitudinal wave light is a transverse wave, waving a rope is too. Both of these are illustrated by the sine function.
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