Sonar is used to determine the speed of an object. A 38.0-kHz signal is sent out, and a 40.0-kHz signal is returned. If the speed of sound is 341 m/s, how fast is the object moving?

Respuesta :

Answer:

The velocity is  [tex]v = 8.743 \ m/s[/tex]

Explanation:

From the question we are told that

    The frequency of the signal sent out  is  [tex]f_s = 38.0 \ kHz = 38.0 *10^{3} \ Hz[/tex]

    The frequency of the signal received is  [tex]f_r = 40.0 \ kHz = 40.0 *10^{3} \ Hz[/tex]

     The  speed of sound is  [tex]v_s = 341 \ m/s[/tex]

Generally the frequency of the sound received is  mathematically represented as

         [tex]f_r = f_s [\frac{v_s + v}{v_s - v} ][/tex]

where v is the velocity of the object

       =>      [tex]40 *10^{3} = 38 *10^{3} * [\frac{341 + v}{341 - v} ][/tex]

       =>      [tex]1.05263 = \frac{341+v }{341-v}[/tex]

       =>   [tex]358.94 - 1.05263v = 341 + v[/tex]

      =>    [tex]17.947 = 2.05263 v[/tex]

      =>    [tex]v = 8.743 \ m/s[/tex]