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!

Homework Help: Frequency heard, need someone to check

  1. Mar 1, 2010 #1
    1. The problem statement, all variables and given/known data

    A train is traveling 30 m/s in still air. The frequency of the train whistle is f = 250 Hz. What frequency is head by a passenger on a train moving in the opposite direction at 18 m/s and approaching the first train? The velocity of sound in air is 344 m/s.

    2. Relevant equations

    F = [(1(+/-) (Velocity listener)/velocity sound) / (1(+/-) (Velocity source)/velocity sound)] *frequency

    3. The attempt at a solution

    Since the listener is moving towards the source and the source is moving towards the listener the forumula becomes

    F = [(1+(Velocity listener)/velocity sound) / (1 - (Velocity source)/velocity sound)] *frequency

    After plugging in the numbers i got 288Hz, is that correct?

    it makes sense because the listener would hear a higher frequency b/c the source is moving towards the listener

    thanks
     
  2. jcsd
  3. Mar 1, 2010 #2
    so, is it right?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook