A ship approaching a seaport at 10 km/h sends a sonic signal of frequency of 1000 Hz. What is the apparent frequency of the signal as received by a receiver on the seaport?
Correct answer: C. 1008 Hz
- A. 984 Hz
- B. 1000 Hz
- C. 1008 Hz
- D. 1210 Hz
Explanation
Frequency = 1000 HzSpeed of ship = 10 km/h = 2.78 m/sSonic signal speed = 340 m/sApparent frequency is found as:f' = vsound / (vsound - vship) x ff' = 340 / (340 - 2.78) x 1000f' = 1008 Hz
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Progressive waves transfer energy through oscillations, with wavelength, frequency, amplitude and wave speed related by v = fλ; sound speed depends on the medium. Superposition produces interference and stationary waves in strings and organ pipes, while simple harmonic motion describes the oscillation itself and must be distinguished from wave propagation.
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