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!

Quick speed of sound question?

  1. Dec 20, 2012 #1
    A swimmer sees a parachutist hit the water and hears the impact twice, once through the water and the second time through the air, 1.0 s later. How far from the swimmer did the impact occur?
    Vs air = 340 m/s Vs water = 1400 m/s the answer is 450m

    I don't understand what to do :confused:
     
  2. jcsd
  3. Dec 20, 2012 #2
    This is a straightforward rate x time = distance (r t = d) problem.

    Let d = distance from swimmer to splash point.

    In terms of d, how much time does the sound take to get from the splash point to the swimmer in air?

    In terms of d, how much time does the sound take to get from the splash point to the swimmer in water?

    In terms of d, what is the difference between these two times?

    (Actually, the answer is not 450m, it's only 449m, but who's counting?)
     
  4. Dec 20, 2012 #3
    Vsound in air= (340)(2)
    =680m

    V sound in water = (1400)(1)
    =1400

    1400-680
    doesn't equal 450m or 459m
     
  5. Dec 20, 2012 #4
    Hu???

    The answer to my first question was: the amount of time it takes for the sound to travel through the air from the splash to the swimmer is d/340 seconds

    The answer to my second question was: the amount of time it takes for the sound to travel through the water from the splash to the swimmer is d/1400 seconds

    The answer to my third question was: the difference between these two times is (d/340) - (d/1400) =1 second

    Are you able to solve this equation for the distance d? If so, what do you get for d?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Quick speed of sound question?
  1. Quick Sound Question (Replies: 2)

Loading...