Help Needed: Solving y = A sin({2*10^6 ({\pi / 3 -\pi t }) + \phi })

[MichaelTam]

Homework Statement

Exercise

Relevant Equations

$v = f \lambda , s({x,t}) = A sin({k x - \omega t + \phi})$, other statements are provided in the picture.

I know so $y = A sin({2*10^6 ({\pi / 3 -\pi t }) + \phi })$
There still some unknown I cannot find, can anyone give me some hint please?

 

[MichaelTam]

But how can I find t?$\lambda = 3$ because $k = 2 \pi/3 = 2 \pi/\lambda$

 

[Steve4Physics]

But how can I find t?$\lambda = 3$ because $k = 2 \pi/3 = 2 \pi/\lambda$

The formula $s(x, t) = A sin(k \cdot x - \omega \cdot t + \phi)$ gives you the signal strength ($s$) at a particular position ($x$) and time ($t$). If you wanted the time at which $s$ had some particular value, you would use the formula. But that is not what the question is about.

You simply want the time for the signal to travel a distance of $1.0 \times10^6$ m. So you use:

$time = \frac {distance}{speed}$

You know the distance is $1.0 \times 10^6$ m. So the real question is can you find the speed ($v$) of the wave from the data supplied?

Edit: minor changes to improve wording.