I must use the wave equation to to find the speed of a wave.

1. The problem statement, all variables and given/known data
I must use the wave equation to to find the speed of a wave.

y(x,t) = (3.0mm) sin [(4.00mm^-1)x - (7.00 s^-1)t]

2. Relevant equations

Here's the wave equation. It has strange symbols.
(∂^2 y) / (∂ x^2) = (1 / v^2) ((∂^2 y)/ (∂^2 t)

3. The attempt at a solution

There's no way that I can attempt this solution if I don't know how to use this formula.
Do I just take the derivative.
Last edited:
Nevermind. I figured it out. V = (w/k)

k= 4.00 mm^-1
w = 7.00 s^-1

V= 7/4 = 1.750 m/s
I don't think your relevant equation is relevant for this problem. You have the equation of the wave for y-position as a function of x-position and time. What do you know about taking derivatives of position functions with respect to time?
I know how to find Velocity and Acceleration, but when I derive these equations, I have a bit of trouble.

The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving