In: Physics
Suppose that two speakers are connected to a single nail with two strings to form a triangular shape. One string has a 3rd harmonic wave of 300 Hz and weighs 3 g/m. The other string has a fundamental frequency of 400 Hz and weighs 4 g/m. Both strings have a tension of 2N
When the speakers play at 1600 Hz, what interference happens at the location of the nail?
Speed of sound is 343 m/s
Third harmonic of first string is 
 and fundamental frequency of second string 
Third harmonic frequency of standing wave 
 and fundamental frequency of standing wave 
Velocity of wave on first string 
 and velocity of wave on the second string 
  
  
That is the distance between first speaker and nail is 
 and  distance between the second speaker and the nail is
Difference between the distances 
 is the path length of two sound waves from two speakers.
Wavelength of sound wave is 
For sonstructive interference at nail, 
For destructive interferece at nail 
 where 
From the values of 
, and 

So 
Hence at the position of nail, destructive interference happens .