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Physics, 13.07.2019 21:10 joanna3895

Stealth submarines. the reflection of sound waves off the hull of a submarine is one of the most important methods of their detection (another is the disturbance they create in the local terrestrial magnetic field). to avoid detection, submarines are coated with rubber (or rubberlike substances). a sonar operates at 10 khz and produces a signal of power po-1 kw transmitted uniformly in a 5° circular cone, used to detect a submarine at a depth of 300 m. assume the reflection off the submarine also propagates back in a 5° circular cone and that the power that penetrates into the rubber coating is dissipated within the coating. the top surface area of the submarine is 65 m2 a. calculate the ratio of power received by the sonar from a steel hull submarine and that of a rubber-coated submarine. is this an effective way of reducing the visibility of submarines? b. in theory, the reflection off submarines can be reduced to zero. explain the requirements of the coating to achieve this.

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