timtng
Nov28-03, 09:13 PM
When the tension is 18 N, a string 2.00 m long has a fundamental frequency of 150 Hz.
a.) What is the mass of the string?
b.) With what tension must the string be stretched so that it vibrates in three segments at 150 Hz?
This is what I came up with:
a.) f=v/2L, v=2Lf=2*2*150=600 m/s
v=sqrt(T/μ), v^2=T/μ, μ=T/v^2=18/600^2=.00005 kg/m
M=2*.00005=.0001 kg
b.) L=3λ/2, 2=3λ/2, λ=4/3
v=fλ=150*4/3=200 m/s
v^2=T/μ, T=μ*v^2=.00005*200^2=2 N
My teacher said that I'm very close to getting the answer, but I don't know what I did wrong.
Please help,
Thanks
a.) What is the mass of the string?
b.) With what tension must the string be stretched so that it vibrates in three segments at 150 Hz?
This is what I came up with:
a.) f=v/2L, v=2Lf=2*2*150=600 m/s
v=sqrt(T/μ), v^2=T/μ, μ=T/v^2=18/600^2=.00005 kg/m
M=2*.00005=.0001 kg
b.) L=3λ/2, 2=3λ/2, λ=4/3
v=fλ=150*4/3=200 m/s
v^2=T/μ, T=μ*v^2=.00005*200^2=2 N
My teacher said that I'm very close to getting the answer, but I don't know what I did wrong.
Please help,
Thanks