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Q & A: Measuring the speed of sound?

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Most recent answer: 10/04/2011
Q:
How can the speed of sound be calculated and how does a starting pistol allow you to do this?
- Shashin Sood (age 12)
Blackpool
A:
As you probably know, the speed, v, is related to distance and time  by v = d/t.   If you know how far away from the starting pistol you are, d, and you know the difference in time between the starter's pulling the trigger and when the sound reaches your ear, t, then you can calculate the answer.  The time, t, can be measured if you can see the flash of the gun and start your stop-watch.  If you halt the watch when you hear the report, that's it. 
This analysis depends on the fact that the speed of the light flash is very, very much larger than the speed of sound.  If it isn't then you would have to make a small correction which in this case is trivially small.

LeeH

(published on 10/04/2011)

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