# Sinusoidal Wave Problem

jpond89

## Homework Statement

Consider the sinusoidal wave in the figure, with the wave function below.

At a certain instant, let point A be at the origin and point B be the first point along the x-axis where the wave is 60.0° out of phase with point A. What is the coordinate of point B?

y = (15.0 cm) cos(0.157x - 50.3t)

and I am not allowed to post the image but here's some helpful information:
its a cosine graph, and $$\lambda$$ = 40 cm, T = 0.125 s, f = 8.00 hz, k = 0.157 rads/cm

## Homework Equations

Some equations that I have are:
k=2$$\pi$$/$$\lambda$$
v=$$\lambda$$*f
y=Asin(kx-$$\omega$$t)

## The Attempt at a Solution

What I have tried so far is:
y=15*sin((.157)x-(50.3)t + $$\pi$$/3)
The example says " The vertical position of an element of the medium at t = 0 and x = 0 is also 15.0 cm "
The only problem is that I am really stuck and I cannot seem what to set the 60.0$$\circ$$ equal to. Help would be much appreciated! Thank you!

## Answers and Replies

Staff Emeritus
Would x = 6.37 * $$\pi$$ because that would make it ($$\pi$$/3 -50.3t)