Classifying standing waves and their frequencies

[Dalip Saini]

Homework Statement

40-cm long string, with one end clamped and the other free to move transversely, is vibrating in its fundamental standing wave mode. If the wave speed is 320 cm/s, the frequency is[/B]

• 
  
  A
  
  16 Hz
• 
  
  B
  
  8 Hz
• 
  
  C
  
  32 Hz
• 
  
  
  D
  
  2 Hz
• 
  
  E
  4 Hz

Homework Equations

f = v/2L
because its fundamental

The Attempt at a Solution

I thought all one had to do was (320)/2(40) = 4Hz, but the answer is 2Hz. I don't understand why

 

[ehild]

Homework Statement

40-cm long string, with one end clamped and the other free to move transversely, is vibrating in its fundamental standing wave mode. If the wave speed is 320 cm/s, the frequency is[/B]

• 
  
  A
  
  16 Hz
• 
  
  B
  
  8 Hz
• 
  
  C
  
  32 Hz
• 
  
  
  D
  
  2 Hz
• 
  
  E
  4 Hz

Homework Equations

f = v/2L
because its fundamental

The Attempt at a Solution

I thought all one had to do was (320)/2(40) = 4Hz, but the answer is 2Hz. I don't understand why

The wavelength is not 2L.