Simple Wavelength Problem (wire of fixed length vibrating)

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JoeyBob
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Homework Statement
See attached
Relevant Equations
wavelength = 2L/N
When the question says 8 antinodes, doesn't that mean N=8? but when I do 2L/8, I get 0.24.

To get the right answer you do 2LN, but that doesn't make sense to me for I thought the equation was 2L/N??
 
Attachments
  • Text problem: A wire of length 0.96m has mass per unit length μ = 1.7×10^-3 kg/m. This wire is under tension 93N and is held rigid at both ends. The string vibrates in a standing wave with 8 antinodes. What is the wavelength of this vibration? Answer in meters.
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Discussion

JoeyBob said:
Homework Statement:: See attached
Relevant Equations:: wavelength = 2L/N

When the question says 8 antinodes, doesn't that mean N=8? but when I do 2L/8, I get 0.24.

To get the right answer you do 2LN, but that doesn't make sense to me for I thought the equation was 2L/N??
Are you saying the official answer is 16 times the length of the wire? Bizarre.
 
I think the answer is wrong. There are 2 anti-nodes per wave length. Since you have 8 anti-nodes, there are 4 wavelengths on the wire. Therefore the wavelength is .24m which is what you got if you add units.
 
Last edited:
haruspex said:
Are you saying the official answer is 16 times the length of the wire? Bizarre.
Yeah the correct answer is 15.36, I guess its just wrong.
 

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