How Do You Calculate Frequency, Wavelength, and Speed from a Wave Equation?

[cse63146]

Homework Statement

The displacement of a wave traveling in the positive x-direction is $$D(x,t) = (3.5cm)sin(2.7x - 124t)$$, where x is in m and t is in s.

What are the frequency, wavelength, and speed?

Homework Equations

The Attempt at a Solution

Not sure where to start. Can someone point me in the right direction?

 

[Kurdt]

This might help:

http://hyperphysics.phy-astr.gsu.edu/Hbase/waves/wavsol.html#c2

 

[cse63146]

so what you're saying is that $$D(x,t) = (3.5cm)sin(2.7x - 124t) =Asin(kx - \omega t)$$

If that's true than A = 3.5cm = 0.035m. k = 2.7 and $$\omega = 124$$

and I know that
$$v = \frac{\omega}{k} = \frac{124}{2.7} = 46m/s$$

and

$$\lambda = \frac{2 \pi}{k} = \frac{2 \pi}{2.7} = 2.33m$$

$$v= f \lambda \Rightarrow f = \frac{v}{\lambda} = \frac{46}{2.33} = 14.7Hz$$

 

[Kurdt]

Yes from a glance that looks ok.

 

[Snazzy]

Check your calculation of frequency.

 

[Kurdt]

Check your calculation of frequency.

Ahh yes, but I presume that was just a typo on the posters part.

 

[cse63146]

Check your calculation of frequency.

Thanks, it should be 19.7Hz.