Waves and sound question

  • Thread starter ladolce
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  • #1
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Homework Statement



The speed of a transverse wave on a string is 420 m/s, and the wavelength is 0.14 m. The amplitude of the wave is 1.5 mm. How much time is required for a particle of the string to move through a total distance of 1.0 km?

Homework Equations



λ x υ= v

The Attempt at a Solution



λ x υ= v
υ= v/λ= 420/0.14= 3000
(1000meters)/(0.00152)= (4.444 x 108) T, where T is the period
t= (4.444 x 108)/ 3000= 1.481 x 10^5

i dont get what i'm doing wrong :(
 

Answers and Replies

  • #2
berkeman
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Wow, are you and brookelynn3 in the same class? With the same typo in the question you're posting? How can a particle on the string move a km?

:cry:Ok I don't know exactally what I am doing wrong here, someone please help!:cry:

The speed of a transverse wave on a string is 400 m/s, and the wavelength is 0.19 m. The amplitude of the wave is 1 mm. How much time is required for a particle of the string to move through a total distance of 1.0 km?


I tried to solve for this by:
v=lamda/T so..
400=.19/t which equals a time of
.000475 seconds per cycle and i thought if I want 1000m (1km) i need to go 1000m/.19m to get how many cycles are necessary, that equals 5263.15 cycles to go 1000 meters so...
5263.15 cycles (.000475m/cycle)=2.5 seconds to complete all the cycles that equals 1000 meters or 1 km.
Except when I input this into my computer, its saying its wrong. can anyone pelase tell me what I am missing???
 
  • #3
Astronuc
Staff Emeritus
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How does the total lateral displacement during one period relate to the amplitude of the wave?

Measuring from zero displacement, the particle moves to full deflection on one side, back to zero to full deflection on the other side, and back to zero in one period.
 
  • #4
berkeman
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Ah, I see that your question has slightly different numbers (weird), and I also see where andrevdh gives a good hint at the end of the other thread about the total distance that a particle on the string travels up and down....

Just click on the green arrow box in the quote to get to the original thread from the last few days.
 

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