A source of sound emitting a 1200 Hz note travels along a straight line at a speed of 170 m/s. A detector is placed at a distance of 200 m from the line of motion of the source.
Find the frequency of sound received by the detector at the instant when the source gets closest to it.

Explanation

To solve the problem of finding the frequency of sound received by the detector when the source is closest to it, we can use the Doppler effect formula. Here are the steps to arrive at the solution:

### Step 1: Understand the Doppler Effect
The Doppler effect describes the change in frequency (or wavelength) of a wave in relation to an observer who is moving relative to the wave source. When the source of sound is moving towards a stationary observer, the frequency observed increases.

### Step 2: Identify Given Values
- Frequency of the source, \( f_s = 1200 \, \text{Hz} \)
- Speed of the source, \( v_s = 170 \, \text{m/s} \)
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