# A speed of sound question

1. Dec 14, 2016

### thetexan

Let's assume a speed of sound of approximately 740 mph at sea level.

If I there are two aircraft traveling in formation 1 mile apart (one in front of the other) at 730 miles per hour, how long will it take for the sound of single gunshot fired from the trailing aircraft to reach the lead aircraft?

I say the sound is traveling at 740mph + the 730mph of the trailing aircraft therefore the sound is closing the distance at 740mph so the time is 3600/740=4.86 seconds.

Is this a correct assumption?

tex

2. Dec 14, 2016

### Staff: Mentor

I moved the thread to our homework section.
No. It does not matter where sound comes from, it always moves at 740 mph relative to the air.

3. Dec 14, 2016

### thetexan

So, am I correct that the closure rate of the sound from the trailing aircraft to the lead aircraft is 10mph relative? Which would mean the gunshot would be heard 6 minutes after the event? Is this approximately correct?

tex

PS. I'm 62, not taking classes, and this is not homework, FYI. If that makes any difference.

4. Dec 14, 2016

### Staff: Mentor

Right.

The forums are sorted by the type of question, it doesn't matter if it is an actual homework assignment - the question is homework-like.