Velocity in the stretched string is
v = sqrt(TL/m)
For the 3rd harmonic λ=2L/3
λ=v/f => v= λf=2Lf/3
sqrt(TL/m)= 2Lf/3
TL/m=(2Lf/3)²
m=9TL/4L²f²=9T/4Lf²=
=9•100/4•1.8•79²=0.02 kg=20 g
A tight uniform string with a length of 1.80 m is tied down at both ends and placed under a tension of 100 N. When it vibrates in its third harmonic, the sound given off has a frequency of 79.0Hz .
Part A
What is the mass of the string?
1 answer
1 answer