# Homework Help: Ξ cm = 4.9 sin (1.06 x - 0.77 t) - Determine Travelling Speed of Wave

1. Jan 17, 2010

### 05holtel

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

The equation of a wave along the x-axis is given as: ξ cm = 4.9 sin (1.06 x - 0.77 t)
in which ξ is the displacement. Units on the right hand side are 1/cm for К and 1/s for ω.
Determine the the traveling speed of the wave.
Express the result in the unit m/s and to three significant figures. If you must use scientific notation, please enter as follows: e.g. 0.000123 = 1.23E-4. Only answer in numerical values, no units. For negative numbers, leave no space between the negative sign and the number: e.g. right: -1.00, wrong: - 1.00.

2. Relevant equations

I would think V= w/k

3. The attempt at a solution

V = 0.77/1.06
= 0.726

2. Jan 17, 2010

### rl.bhat

lambda = 2*pi/1.06
frequency f = 2*pi/077
v = f*lambda.
Try this one.

3. Jan 18, 2010

### 05holtel

(2*pi/1.06)(2*pi/0.77)
v = 48.3

It says it is wrong. Are the units m/s?

4. Jan 18, 2010

### vela

Staff Emeritus
Your initial method is correct. Try writing in the units to see what units your answer is in and then convert it if necessary.