A pendulum has a frequency of 4 vibrations per second. An observer starts the pendulum and fires a gun simultaneously. He hears the echo from the cliff after 6 vibrations of the pendulum. If the velocity of sound in air is 340 m/s, find the distance between the cliff and the observer.

Explanation

To solve the problem step by step, we will follow these calculations:

### Step 1: Determine the time taken to hear the echo
The frequency of the pendulum is given as 4 vibrations per second. The observer hears the echo after 6 vibrations of the pendulum.

To find the time taken to hear the echo, we can use the formula:
\[
\text{Time} = \frac{\text{Number of vibrations}}{\text{Frequency}}
...