# What multiplicative factor does speed and wavelength change by?

1. Sep 10, 2011

### Emmanuel0

Consider a wave on a string with constant tension. If the frequency of the wave is doubled, by what multiplicative factor does a) the speed and b) the wavelength change?

I dont really know how to begin to answer this question. The best i could think of is using
v=wavelenght x f and then putting a square route on the f (frequency) and solving for wavelenght and i guess v (speed of the wave) from there.

If anyone know where i can find more problems like this (aside from my text book) let me know as i am really struggling with this and i want to get a better understanding of it.

2. Sep 10, 2011

### vela

Staff Emeritus
What other equations do you have that apply to a wave on a string?

3. Sep 10, 2011

### Emmanuel0

v= square root(F/U)

4. Sep 10, 2011

### vela

Staff Emeritus
Good, so that's where F is the tension in the string and $\mu$ is its mass per unit length. How do the wavelength and frequency affect those quantities, if at all?

5. Sep 10, 2011

### Emmanuel0

I am not sure, increasing tension shortens wavelength.

6. Sep 10, 2011

### vela

Staff Emeritus
You might find it useful to play around with this simulation.

http://phet.colorado.edu/sims/wave-on-a-string/wave-on-a-string_en.html

Set the damping to 0 and the end of the string to "no end." Then set the left end oscillate. You can adjust the frequency and tension in the string and see what happens.

I would suggest first leaving the frequency fixed and playing around with the tension. See what happens to the speed and wavelength of the wave.

Then try the opposite. Leave the tension fixed and vary the frequency. What happens to the speed and wavelength of the wave?

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