1. The problem statement, all variables and given/known data A submarine can use sonar (sound traveling through water) to determine its distance from other objects. The time between the emission of a sound pulse (a “ping”) and the detection of its echo can be used to determine such distances. Alternatively, by measuring the time between successive echo receptions of a regularly timed set of pings, the submarine’s speed may be determined by comparing the time between the echos to the time between pings. Assume you are the sonar operator in a submarine traveling at a constant velocity underwater. Your boat is in the eastern Mediterranean Sea, where the speed of sound is known to be 1522 m/s. If you send out pings every 2.00 s, and your apparatus receives echoes reflected from an undersea cliff every 1.98 s, how fast is your submarine traveling? 2. Relevant equations 3. The attempt at a solution What I did was I tried to find the distance the cliff was from the submarine (1522x0.99)=1506.78 m. Although I'm not sure whether this applies when the submarine is moving. I am stuck and do not know what to do next. Please help me out.