# Displacement of a Wave

1. Apr 9, 2008

### cse63146

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

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?

2. Relevant equations

3. The attempt at a solution

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

2. Apr 9, 2008

### Kurdt

Staff Emeritus
3. Apr 9, 2008

### 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

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

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

Last edited: Apr 9, 2008
4. Apr 9, 2008

### Kurdt

Staff Emeritus
Yes from a glance that looks ok.

5. Apr 9, 2008

6. Apr 9, 2008

### Kurdt

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

7. Apr 9, 2008

### cse63146

Thanks, it should be 19.7Hz.