# Amplitude of velocity (Travelling wave)

1. May 10, 2015

### Alex_Neof

1. The problem statement, all variables and given/known data
A wave traveling along a long string has the form:

$y(x,t) = 20sin(3x - 2t),$ where $x$ is in metres and $t$ is in seconds.

Find the amplitude of the velocity of any particle of the string.

2. Relevant equations

Do I just find $\frac {\partial y}{\partial t}$ ?

3. The attempt at a solution

So $\frac {\partial y}{\partial t} = -40cos(3x - 2t)$, therefore the amplitude of the velocity of any particle of the string is $-40 m/s$. Absolute value $40 m/s$.
Or is it more involved?

2. May 10, 2015

### TSny

Your work looks good to me. However, the units for y are not given. 20 m seems like a very large amplitude for a wave on a string.

3. May 10, 2015

### Alex_Neof

ahaha !. The is making me laugh. Yeah the question didn't give the units for y. Thanks TSny.