# Homework Help: How to figure wavelength

1. Feb 7, 2009

### phys1618

1. The problem statement, all variables and given/known data
it's stated that 2.5meters separated a trough and an adjacent crest of surfae wave on a lke.

2. Relevant equations

3. The attempt at a solution

At first I thought if the trough to th crest is 2.5meters then i would double that to get the wavelenght from crest to crest. But then when I drew another wave picture, the 2.5 can be the amplitude? so that would make me taking half of the 2.5meters instead?? I think my problrm is not understanding what that statmnt is trying to say. I'm unsure if I would multiply 2.5m by two or divide by half. thanks

2. Feb 7, 2009

### Staff: Mentor

That's how I interpreted the problem statement: The horizontal separation between trough and adjacent crest is 2.5 m. (But I admit that it is ambiguous.)

If 2.5 m is the vertical separation between those two points, then you would not be able to find the wavelength (which is what you are asked to find, right?).

3. Feb 7, 2009

### phys1618

yes, when i first read it, i thought i should double the 2.5m., but in the statemnt is it referrring it has a standing wave or regular wave? am i thinking too much into the problem? is it as simple as it sounds? =x
but you know, you are right, if 2.5 is the vertical separation between the two, I dont think i can find the wavelenght. so go with the first idea?
thank you for the help.

4. Feb 7, 2009

Yes.

5. Feb 7, 2009

### phys1618

=) thank you for your help!