A train standing in a station-yard blows a whistle of frequency 400 Hz in still air. A wind starts blowing in the direction from the yard to the station wit a speed of 10 `ms^(-1)?`. What are the frequeney, wavelength and speed of sound foran observer standing on the station's platform ? Is the situation exactly equivalent to the case when the air is still and the observer runs towards the yard at the speed of 10 `ms^(-1)?`

Explanation

To solve the problem, we need to analyze the situation in two parts: first, when the wind is blowing, and second, when the observer is running towards the source of sound.

### Step-by-Step Solution:

**Step 1: Determine the frequency heard by the observer when the wind is blowing.**
- The frequency of the whistle produced by the train is given as \( f = 400 \, \text{Hz} \).
- Since there is no relative motion between the source (train) and the observer (station platform), the frequency remains the same. Thus, the frequency heard by the observer is:
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