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: How long will it take for the echo to return

  1. Nov 27, 2014 #1
    1. The problem statement, all variables and given/known data
    A submarine sends out a sonar wave that has
    a frequency of 545 Hz. If the wavelength of the
    sound is 2.60 m, how long does it take for the
    echo to return when the sound is reflected from
    a submarine that is 5.50 km away?

    2. Relevant equations

    3. The attempt at a solution
    i used the equation p=1/f and i plugged in frequency and got 0.00183 seconds, the right answer should be around 7-8 seconds
  2. jcsd
  3. Nov 27, 2014 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Well let's see here. Is it perhaps you calculated the period of one wavelength and overlooked the fact that it takes more than one wave of length 2.60 m to cover the distance of 5.50 km to the object and then 5.50 km back again to the sub?
  4. Nov 27, 2014 #3
    thank you so much, i finally got the right answer!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted