# Homework Help: Need help with a SOUND question~ ><

1. Oct 26, 2009

### tx_179

Need help with a SOUND question~!!><

A bat flying in a cave emits a sound pulse and receives its echo in 2.9 s. How far away is the cave wall?

2. Oct 26, 2009

### CaptainEvil

Re: Need help with a SOUND question~!!><

Do you know of an equation relating speed, distance and time?

What is the speed of sound waves in a 'cave' (i.e in air)?

Don't forget that the sound needs to travel to the cave wall AND back

3. Oct 26, 2009

### tx_179

Re: Need help with a SOUND question~!!><

v=d/t
340m/s

4. Oct 26, 2009

### CaptainEvil

Re: Need help with a SOUND question~!!><

And you can't solve it from here???

5. Oct 26, 2009

### tx_179

Re: Need help with a SOUND question~!!><

So, do you take 2.9 times by 2??

6. Oct 26, 2009

### CaptainEvil

Re: Need help with a SOUND question~!!><

re-arrange your velocity equation, plug in the numbers and solve for distance. Just know, that the distance you end up with will be the TOTAL distance the sound waves traveled, from the bat to the wall and back to the bat.

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