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: Doppler Effect of Sound

  1. Feb 12, 2012 #1
    1. The problem statement, all variables and given/known data
    A policeman detects a drop of 10% in the pitch of the horn of a motor car as it crosses him. If the velocity of sound is 330ms^-1, calculate the speed of the car.

    2. Relevant equations
    f2 = f1 [v - v(listener)]/[v - v(source)]
    where f2 = apparent frequency
    f1 = true frequency

    3. The attempt at a solution
    I'm confused about how the car crosses him. Please help.
  2. jcsd
  3. Feb 12, 2012 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Welcome to Physics Forums.

    At first, the car is moving toward the policeman at speed vsource. It passes by the policeman, and is then moving away from him at the same speed.
  4. Feb 16, 2012 #3
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook