Acoustics and Frequency Question (easy)

[sobo22]

1. Two nearly identical forks one of which has a frequency of 384Hz produce 7 beats per second when they vibrate at the same time. A small clamp is placed on the 384Hz fork and then only 5 beats per second are heard. What is the frequency of the other fork?

Homework Equations

I honestly have no idea

The Attempt at a Solution

Well I know the answer is 377 and I've been trying to work backwards but the only thing I can think of is 5 +/- uncertainty then 2 for the change in beats so 7? But even then I have no idea why it would be 377 vs 381.. Can someone please help me out I'm so lost

 

[Sebastian]

Look up the equation for beating (Wikipedia has it, for example).

 

[sobo22]

hey thanks man. So would it be

f = f1 - f2

f2 = f1 - f

f2 = 384 - 7 (amount of beats) = 377?

what about the 7 to 5 beats thing, is that just irrelevant filler?
does someone mind explaining the concept of it? I am still lost

is it because 7 beats are heard so that means there is a difference of 7 hz?

 

[olivermsun]

At first there are 7 beats between the forks, so you know their frequency difference -- but do you actually know whether the second fork is higher or lower than 384 Hz?

What happens to the frequency when you attach a "small" clamp to the 384 Hz fork?