Answer:410 Hz
Explanation:
It is given that frequency of tuning fork is 415 Hz and hears a beat of 5 beat per second
so untuned frequency must be either 410 Hz or 420 Hz because beat frequency is the difference in frequency of two notes. Â
When she tightens the string the beat frequency decrease
and velocity [tex]v=\nu \lambda [/tex]
where [tex]\nu =frequency[/tex]
[tex]\lambda =wavelength[/tex]
[tex]v=velocity[/tex]
[tex]v=\sqrt{\frac{T}{\mu }}[/tex]
where T=tension
it T increase v also increases and from 1 st equation frequency is also increasing therefore untuned frequency must be 410 Hz because beat frequency is decreasing. Â Â Â Â Â Â Â Â Â Â