# Help help help on speed of sound

1. Apr 13, 2009

### dlre

1. The problem statement, all variables and given/known data

the air temperature is 20 degree celcius. you are swimming underwater when you hear a boat noise. then 305s later, you hear a crash. if the speed of sound in wter is 1450m/s, how long after the crash does your friend on the dock beside oyu hear the crash?

2. Relevant equations

??

3. The attempt at a solution

??

2. Apr 13, 2009

### Pengwuino

Do you know the speed of sound in air?

3. Apr 13, 2009

### dlre

346m/s?

4. Apr 14, 2009

### Pengwuino

Ok so you know the time it takes for the sound to transverse a distance in a certain medium is $$t = \frac{d}{{v_{medium} }}$$. You really don't know the "distance" because it's not actually stated in the problem that the crash occured immediately after the boat sound is heard but you CAN determine the ratio of the time sound waves take to reach each person using the equation.