A submarine sonar system sends a burst of sound with a frequency of

[k0k]

A submarine sonar system sends a burst of sound with a frequency of 325Hz. The sound wave bounces off an underwater rock face and returns to the submarine in 8.50s. If the wavelength of the sound is 4.71m, how far away is the rock face? (Ans: 6.51km )

--
v=fλ

λ=wavelength
f=frequency
v=velocity
--
v=fλ
v=325Hz X 4.71m
=1530.75m/s

v=d/t
d=vt
= 1530.75m/s X 8.50s
=13011.375m
=13011.375m/2
=6505.6875m

=6.51km.

What exactly am I doing wrong here? ..

 

[Doc Al]

v=dt
d=v/t

This is not correct. What's the definition of speed? (When in doubt, check the units.)

Also: Don't forget that the sound makes a round trip.

 

[k0k]

Oh, my bad, a silly error. I got it now. Thanks for the tip on sound making a round trip. : )