How Do You Calculate the Wavelength of Colliding Waves?

[ixerr]

Homework Statement

Two sinusoidal waves with equal wavelengths travel along a string in opposite directions at 7.72 m/s. The time between two successive instants when the antinodes are at a maximum height is 0.324 s. What is the wavelength (in m)?

Homework Equations

vt=x
Also,
Propagation speed = wavelength * frequency = wavelength / period time

The Attempt at a Solution

I tried many, many different ways to solve this equation but ultimately I keep getting the wrong answer.. Here is one of the attempts:
The distance between two successive antinodes or two successive nodes is equal to the wavelength of the wave. I figured out the distance based on the speed of the wave and the time between two antinodes with vt = x (since there is no acceleration).
(7.72)(0.324)= 2.50128 m
Yet it is not the right answer? Can anyone give me any more insight on what I can do..?

 

[BruceW]

The question is a bit vague... does it mean both waves are moving at 7.72 m/s in opposite directions? so their relative velocity is 15.44 m/s ? And it seems to suggest standing waves, but it doesn't mention the end points of the string, so really the two waves could have any phase difference.

If I was guessing, I'd say each of the waves is moving at 7.72 m/s so their relative velocity is 15.44 m/s and I'd guess the situation is standing waves caused by the string being fixed at one end. But what do you think? was there more information?

 

[ixerr]

Yes! :) I got the answer, the velocity was 15.44 m/s. Thanks!

 

[BruceW]

alright, cool