How far from a cliff should a boy stand in order to hear the echo of his clap 0.9s later? (Speed of sound in air = 330 ms-1)?

2 d = 330 (0.9)

To determine how far the boy should stand from the cliff in order to hear the echo of his clap 0.9 seconds later, we need to use the equation:

Distance = Speed × Time

First, we need to find the total time it takes for the sound to travel from the boy to the cliff and back to the boy. The sound travels from the boy to the cliff and then reflects back to the boy, covering the same distance twice.

So, the total time taken for the sound to travel back and forth (i.e., the round trip time) is twice the echo delay time, which is 0.9 seconds.

Total Round Trip Time = 2 × Echo Delay Time
= 2 × 0.9 seconds
= 1.8 seconds

Now, we can plug in the speed of sound in air, which is given as 330 m/s, and the total round trip time of 1.8 seconds into the distance equation to find the distance:

Distance = Speed × Time
= 330 m/s × 1.8 seconds

Calculating this:

Distance = 594 meters

Therefore, the boy should stand approximately 594 meters away from the cliff in order to hear the echo of his clap 0.9 seconds later.