There is a sunken ship at a depth of 50 m in a sea. From the surface of sea, waves are sent to locate it. Find the time when the wave after reflection will reach the surface. State whether echo is heard or not? Give reason. Take speed of sound in water = 1400 m `s^(-1)`

Explanation

To solve the problem, we need to determine the time taken for sound waves to travel to the sunken ship and back to the surface. We will follow these steps:

### Step 1: Identify the given values
- Depth of the ship (d) = 50 m
- Speed of sound in water (v) = 1400 m/s

### Step 2: Calculate the total distance traveled by the sound waves
The sound waves need to travel down to the ship and then back up to the surface. Therefore, the total distance (D) traveled by the sound waves is:
...