Answer:
The other frequency is either 253Hz (the altered tuning frequency vibrates lower) or 259Hz(if the altered tuning frequency vibrates higher):
Explanation:
We have two frequencies: the tuning fork frequency and the altered tuning fork frequency
F1 -----tuning fork frequency
F2-----Altered tuning fork frequency
Fbeat=3
F1=256Hz
To find the alterd tuning fork frequency:
The beat frequency of any two waves is:
Fbeat =|f1 – f2|
i.e we have two choices
for frequency tied to length increase (wavelength increases as length increases, therefore frequency decrease (the altered tuning frequency vibrates lower): Fbeat = f2-f1
F2=F1-Fbeat
F2= 256-3
=253Hz
For frequency tied to length decrease wavelength increases as length increases, therefore frequency also increases(the altered tuning frequency vibrates higher) : Fbeat = -(f2-f1)
F2= Fbeat+F1
= 256+3
= 259Hz
Note that a wavelength increase means a decrease of frequency because v = fλ
