A string `120 cm` in length and fixed at both ends sustains a standin wave, with the consecutive points of the string at which the displacement amplitude is equal to `3.5 mm` (not maximum) being seperated by `15.0 cm`. Find the maximum displacement amplitude. To which overtone do these oscillations correspond ?

Answer

`a_(max) = 3.5 sqrt(2) mm;` to the third overtone.