Beat frequency from 1.5% tension decrease in cello string

[maninthesuit]

1. Two identical strings on different cellos are tuned to the 440-Hz A note. The peg holding one of the strings slips, so its tension is decreased by 1.5%. What is the beat frequency heard when the strings are played together?
f₁=440Hz; Tension decrease=1.5%2. f(beat)=|f₁-f₂|3.
f₂=440Hz - (440Hz*.015)=433.4Hz
f(beat)=|440Hz-433.4Hz|=6.6Hz

The answer is supposed to be 3.3Hz. I would really appreciate the help. Thanks.

 

[Thundagere]

I think you're missing a key formula here.
Remember that the velocity of the wave on a tensioned string is

v = √(F / µ) where µ is the string density. Use it more conceptually now, and think about the relationship of the force to the velocity, and the velocity to the pitch and wavelength.

 

[maninthesuit]

Thank you very much. I got the right answer now. Much appreciated. :)