A stationary motion detector sends sound waves of frequency 3.00 MHz toward a truck approaching at a speed of 61.0 m/s. What is the frequency of the waves reflected back to the detector?

Explanation

To solve the problem, we will use the Doppler effect formula for sound waves. The steps are as follows:

### Step 1: Identify the parameters
- Frequency of the source (motion detector), \( f_s = 3.00 \, \text{MHz} = 3.00 \times 10^6 \, \text{Hz} \)
- Speed of the truck (observer), \( v_o = 61.0 \, \text{m/s} \)
- Speed of sound in air, \( v = 343 \, \text{m/s} \)

### Step 2: Calculate the frequency received by the truck (observer)
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