# Speed of standing wave

## Homework Statement

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

## Homework Equations

Velocity=(wavelength)(frequency)

I believe is the equation that applies here.

## 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?

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berkeman
Mentor

## Homework Statement

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

## Homework Equations

Velocity=(wavelength)(frequency)

I believe is the equation that applies here.

## 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?
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....?