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Homework Help: Doppler effect quick question

  1. Jul 26, 2009 #1
    doppler effect quick question!!!!

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

    An ambulance traveling at speed 31 m/s is producing a loud sound of frequency 895 Hz. You see the ambulance in your rear view mirror as the ambulance approaches you and you slow down to 14 m/s as a law obeying citizen (hehehe we know now).

    2. Relevant equations

    fo=fs((v +- Vo)/(v+-Vs))

    should it be:

    895 (330-14)/(330-31)???

    3. The attempt at a solution
  2. jcsd
  3. Jul 27, 2009 #2


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    Homework Helper

    Re: doppler effect quick question!!!!

    You are wright.
  4. Jul 27, 2009 #3
    Re: doppler effect quick question!!!!

    hi, thanks so much! i got that one... will you look at this one? I feel like I am so close.



    A chunk of carbon steel with density, ρ = 7.84 g/cm3 , is completely submerged in fresh water. The chuck of steel weighs 39 N more in air than in water. Please answer the following:
    (a) Find the buoyant force acting on the chuck of steel.
    (b) Find the the volume of the chuck of steel.
    (c) What is the mass of the chuck of steel?

    2. Relevant equations

    Fw(air)=Fw(water) + 39 N



    BUT I dont know how to find the volume.

    density of air is 1.16 kg/m3
    density of water is 1.0x10^3

    3. The attempt at a solution

    once I get the VOLUME I can find the relative weights by using rho*g*v
    and Fw(water)+ 39N = Fw(air)
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