In the above problem, if some of the sound reaching the target ges reflected back to the rocket as an echo, then what frequency of the echo is detected by the rocket?

Explanation

To solve the problem of finding the frequency of the echo detected by the rocket, we can follow these steps:

### Step 1: Understand the Situation
The rocket is moving towards a stationary target and emits a sound wave of frequency \( f = 500 \, \text{Hz} \). The rocket moves at a speed of \( v_r = 220 \, \text{m/s} \) towards the target. The sound wave reaches the target and is reflected back as an echo.

### Step 2: Calculate the Frequency Detected by the Target
Using the Doppler effect formula, we previously calculated the frequency of the sound detected by the target when the rocket emitted the sound. The frequency detected by the target \( f' \) is given by:

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