A SONAR system fixed in a submarine operates at a frequency 40.0kHz. An enemy submarine moves towards the SONAR with a speed of 360 km`h^(-1)`. What is the frequency of sound reflected by the submarine ? Take the speed of sound in water to be 1450 `ms^(-1)`.

Explanation

To solve the problem of finding the frequency of sound reflected by the enemy submarine using the Doppler effect, we will break the solution into two main steps.

### Step 1: Calculate the apparent frequency received by the enemy submarine

1. **Identify the given data:**
- Frequency of the sonar (source): \( f = 40.0 \, \text{kHz} = 40 \times 10^3 \, \text{Hz} \)
- Speed of sound in water: \( V = 1450 \, \text{m/s} \)
- Speed of the enemy submarine (observer): \( V_o = 360 \, \text{km/h} = \frac{360 \times 1000}{3600} = 100 \, \text{m/s} \)
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