5.5 and 5.6 Pitch and Frequency,, calculations sound

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Cette leçon contient 23 diapositives, avec quiz interactifs, diapositives de texte et 1 vidéo.

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Slide 1 - Diapositive

Slide 2 - Diapositive

Recap
Four wave properties:
1. Wave length
2. Amplitude
3. Frequency 
4. Speed

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v=fλ

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Slide 8 - Vidéo

You saw the frequency increasing. What happened to the pitch if the frequency increases? As the f increases pitch increases too.
       A. What was the highest frequency you heard?
Somwhere between 20 to 23000 Hz.

      

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For this exercise use the table at the previous page. You only need two names.
Animal which can hear the highest frequency
Animal that hears the lowest frequency
Neither of the two choices
Elephant
Porpoise
Bats
Dog
Cat
Chicken
Killer Whale

Slide 11 - Question de remorquage

What frequency can be heard by all animals?

A
16 Hz
B
2.000 Hz
C
150.000 Hz
D
None of the one mentioned

Slide 12 - Quiz

Slide 13 - Diapositive

Two formulas to calculate the speed of sound
speed=timedistance
speedofsound=wavelengthfrequency

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speed=timedistance
v=td
  • v: speed in m/s
  • d: distance in m
  • t: time in s

3=26

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  • vs: the speed of sound (m/s)
  • λ: wavelength (m)
  • f: frequency (Hz)

speedofsound=wavelengthfrequency
v= λ • f
6=23

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Formula frequency 
f = 1/T  where,
f: frequency in hertz (Hz)
T: time needed for one vibration in seconds
T=1/f

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Definition supersonic and Mach
Supersonic: faster than speed of sound
Mach 1 = speed of sound in air = 330 m/s
Mach 3 = 330× 3= 990 m/s

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Opgave 
 a sound wave were observed to travel a distance of 700 meters in 2 seconds. Calculate its speed.
Given: d= 700 meter , t= 2 s
Asked: v=?
v=d/t.  v= 700/ 2= 350 m/s

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Opgave
What is the speed of a sound wave with a frequency of 2 kHz and a wavelength of 35 cm? 
Given: f= 2kHz. = 2000 Hz.    
λ= 35 cm = 0.35 m
Asked: v=?  
v = λ • f = 0.35× 2000= 700 m/s

Slide 22 - Diapositive

Calculating the speed of sound  using echoes
A girl stands 102 m away from a wall and claps two wooden blocks together. She hears an echo after 0.6 s.Calculate the speed of sound in air. 
Given: t = 0.6 s.  d=102 + 102 = 204 m.
Asked: v=?
v=d/t  = 204÷ 0.6=340 m/s 
Or  v=d/t. v= 102÷ 0.30 = 340 m/s

Slide 23 - Diapositive