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To stand or to travel

The velocity of a transverse wave on an infinitely long string is $ c$. At $ t = 0$ the string is flat (i.e., $ y(x,t=0) \equiv 0$) and has velocity distribution $ v_y(x,t=0) = V_{\scriptscriptstyle 0}\sin\left(kx +
\frac{2\pi}{3}\right)$ where $ V_{\scriptscriptstyle 0}$ and $ k$ are constants.
Hint: See LN ``Wave Phenomena I,'' Sec. 5.1.

(a)
Find the particular solution $ y(x,t)$ to the wave equation for the string consistent with the above initial conditions.

(b)
Does the solution found in (a) represent a traveling wave, a standing wave, or neither? If a traveling wave, in what direction is it moving? If a standing wave, re-write your solution for part (a) in the standing wave form $ y(x,t) = A(x)\sin(\omega t)$ and find explicitly the function $ A(x)$ in terms of no other quantities than $ V_{\scriptscriptstyle 0}$, $ c$, and $ k$.



Tomas Arias 2003-10-15