1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Beat Frequency of a trumpet

  1. Feb 20, 2015 #1
    1. The problem statement, all variables and given/known data
    A trumpet player hears 3 beats per second when she plays a note and simultaneously sounds a
    440 Hz tuning fork. After pulling her tuning valve out to slightly increase the length of her
    trumpet, she hears 5 beats per second against the tuning fork. What was her initial frequency?
    a) 437 Hz
    b) 443 Hz
    c) Either a) or b).
    d) 435 Hz
    e) 445 Hz
    2. Relevant equations
    fbeat = |f2-f1|

    3. The attempt at a solution
    I understand how the beat frequency is the difference of the 2 frequencies. So |f1-440| = 3 and |f2-440| = 5. So the first frequency can be 437 or 443 Hz but the answer in only 437 Hz, why?
  2. jcsd
  3. Feb 20, 2015 #2


    User Avatar

    Staff: Mentor

    The tiny increase in length that caused an extra 2 Hz in the beat frequency might provide [what is intended to be] the clue.
  4. Feb 20, 2015 #3

    Quantum Defect

    User Avatar
    Homework Helper
    Gold Member

    Pulling out the tuning slide lowers all of the pitches. I think you are right.

    She could have been flat (437) and pulled out, thinking she was sharp, going even flatter (435). She could also have been a little sharp (443) and pulled out too much, taking her down too far (435).
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Beat Frequency of a trumpet
  1. Beat frequency (Replies: 6)