A car approaching a crossing `C` at a speed of `20 m//s` sounds a horn of frequency `500 H_(Z)` when `80 m` from the crossing . Speed of sound in air is `330 m//s` . What frequency is heard by an observer (at rest) `60m` from the crossing on the straight road which crosses car road at right angles ?

Explanation

To solve the problem step by step, we will apply the principles of the Doppler effect for sound waves.

### Step 1: Understand the scenario
A car is approaching a crossing at a speed of \(20 \, \text{m/s}\) and sounding a horn of frequency \(500 \, \text{Hz}\). The speed of sound in air is \(330 \, \text{m/s}\). The observer is located \(60 \, \text{m}\) from the crossing, and the car is \(80 \, \text{m}\) away from the crossing.

### Step 2: Determine the position of the observer and the car
- The car is approaching the crossing from a distance of \(80 \, \text{m}\).
- The observer is located \(60 \, \text{m}\) from the crossing along a perpendicular road.
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