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: Sound Question

  1. Jan 14, 2008 #1
    1. The problem statement, all variables and given/known data

    The distance between a loudspeaker and the left ear of a listener is 1.90 m.

    (a) Calculate the time required for sound to travel this distance if the air temperature is 20°C.

    2. Relevant equations
    I am not sure, I tried looking in my text...but the only equation I could come up with is velocity = sqroot(ykT/m)
    where y = specific heat, k is the Boltzmann constant, T is the given temp in K, and m is the distance..

    3. The attempt at a solution

    I have no idea where to even start, because only 2 things are known x in meters and the Temp 20 deg or 293 K. Can anyone help me out?
  2. jcsd
  3. Jan 14, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    You need the speed of sound in air. You can either look up the experimental real value or use the ideal gas approximation root(ykT/m) but here m is the molar mass of air not the distance!
    You then use speed and distance to get the time.
  4. Jan 15, 2008 #3
    what equation can you solve for time by having speed and distance?
  5. Jan 15, 2008 #4


    User Avatar
    Science Advisor
    Homework Helper

    Did you realy mean to write that!
    What is the definition of speed?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook