One ultrasound pulse from a ship gives two echoes…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
One ultrasound pulse from a ship gives two echoes. The first comes after , from a shoal of fish. The second comes after , from the sea floor. (Speed of sound in sea water ) Find the depth of the fish, the depth of the sea floor, and the height of the fish above the floor.
Need a reminder? The key ideaShow
An echo travels to the reflector and back: . A separate echo needs at least (a wall at least away in air). SONAR uses ultrasound in sea water, about .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Fish. .
Step 2. Floor. .
Step 3. .
Answer: ; ; above the floor.
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