Physics for IGCSE & O level - Waves And Sounds (Section 4 - No. 30)
How is the depth of the water calculated using echo-sounding?
Distance travelled / time
Speed of sound * time
1/2 * (Speed of sound * time)
Distance travelled - time
הֶסבֵּר
Depth = 1/2 * speed * time, as the sound has to travel down and back.