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# A sonar device on a submarine sends out a signal and receives an echo 5 s later. Calculate the speed of sound in water if the distance of the object from the submarine is 3625 m.

Time (t) taken to hear the echo = 5 s

Distance (d) of object from submarine = 3625 m

Total distance travelled by SONAR during reception and transmission in water = 2d

Velocity (v) of sound in water = $$\frac{2d}{t} = \frac{2 × 3625}{5}$$

$$\Rightarrow v = 1450 \ m/s$$