# How to find a wave eqation?

1. Nov 21, 2012

### RockenNS42

in the form
y(x,t)=Asin(k(x-vt)+δ)
where p is the phase angle

A is .02m
v=22.4m/s
t=0.1s
k=2.80
wavelengh= 2.24m
at time t=0, the dispaclement(y) is 0.01m with dy/dt is negative

Im not sure how to findδ

2. Nov 22, 2012

### Simon Bridge

You'll find there are a couple of bits of information you have not used yet.

3. Nov 22, 2012

### RockenNS42

I was just having the biggest brain fart ever, I figured it out after I posted, but didnt have a chance till now to comment

4. Nov 22, 2012

### Simon Bridge

No worries - sometimes asking a question can be just the thing to unstick the grey matter.
How about posting your answer so anyone else with the same problem will see how you did it?

5. Nov 22, 2012

### RockenNS42

ok well the wave equation is

y(x,t)=Asin(k(x-vt)+δ)
we know A, v,and k and we can sub them in to get
y(x,t)=0.02sin(2.8(x-22.4t)+δ)
and expand
y(x,t)=0.02sin(2.8x-62.8t+δ)

to get δ we take the conditions given @t=0, y=.01m
x=0m( its at the driving end, I left this out in my initial question)
now solving for δ we get δ=0.52
therefore
y(x,t)=0.02sin(2.8x-62.8t+0.52)

6. Nov 22, 2012

### Simon Bridge

Bootiful :) cheers!