All Problems

Elastic Waves. Acoustics.

Problem 4.151

A plane harmonic wave with frequency ω\omega propagates at a velocity vv in a direction forming angles α,β,γ\alpha, \beta, \gamma with the x,y,zx, y, z axes. Find the phase difference between the oscillations at the points of medium with coordinates x1,y1,z1x_{1}, y_{1}, z_{1} and x2,y2,z2x_{2}, y_{2}, z_{2}

Reveal Answer
Δφ=ωv(x1x2)cosα+(y1y2)cosβ+(z1z2)cosγ\Delta \varphi=\frac{\omega}{v}\left|\left(x_{1}-x_{2}\right) \cos \alpha+\left(y_{1}-y_{2}\right) \cos \beta+\left(z_{1}-z_{2}\right) \cos \gamma\right|