Open organ pipe what does 6 beats per second mean?

[yjk91]

Homework Statement

You are playing a note that has a fundamental frequency of 428 Hz on a guitar string of length 56 cm. At the same time, your friend plays a fundamental note on an open organ pipe, and 6 beats per seconds are heard. The mass per unit length of the string is 2 g/m. Assume the velocity of sound is 343 m/s.

(a) What are the possible frequencies of the open organ pipe? (Enter your answers from smallest to largest.)

(b)What is the length of the organ pipe?

The Attempt at a Solution

What does 6 beats per seconds mean?
does it mean that there are 6 nodes?

 

[Ouabache]

What does 6 beats per seconds mean?

What happens when you play two notes close in frequency, notes that are almost but not equal in frequency?

 

[yjk91]

beats?

 

[Ouabache]

Correct, also known as beat frequency. That is what you are hearing at 6 bps. To hear what is going on, you could listen to the 2nd (low frequency) audio example under http://en.wikipedia.org/wiki/Beat_%28acoustics%29" , towards the bottom of that page.
To understand why you are hearing beats (and the mathematical relationship to the two contributing notes), you may want to look at http://hyperphysics.phy-astr.gsu.edu/hbase/sound/beat.html" .