One end of a string 7 m long is moved up and down with simple harmonic motion at a frequency of 70 Hz. The waves reach the other end of the string in 0.4 s. Find the wavelength of the waves on the string.

Question

perl · Answer

Hint: frequency*wavelength=speed

idku · Answer

$\displaystyle v=\frac{L}{t}=\frac{7}{0.4}=17.5$

$\displaystyle f=70$

$\displaystyle f\times \lambda=v$

$\displaystyle 70\times \lambda=17.5$

$\displaystyle 70\times \lambda=0.25~{\rm meters}$

idku · Answer

yeah, I saw "frequency*wavelength=speed" the first time I looked online (our teacher didn't cover this yet assigned for h/w :(  ), so I was thinking about some way of putting it.

idku · Answer

Is this correct or totally ridiculous ?

idku · Answer

Oh, yes, it's correct;)
Thanks!