Speed of standing wave

Spirochete

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

The standing wave in the picture is oscillating at 100 Hz. What is it's velocity?


2. Relevant equations

Velocity=(wavelength)(frequency)

I believe is the equation that applies here.


3. The attempt at a solution

The wavelength from the picture appears to be 20x10-2 meters.

So velocity should equal (20x10-2)(100)= 20 meters per second

But I know this answer is wrong. Where am I going wrong?

Attached Thumbnails

 

berkeman

Why do you say that the wavelength is 20cm? Draw a full cycle of a sine wave -- what does it look like?

Also, be careful with your units. It looks like you are mixing cm and meters in your multiplication and answer....?