Purchase Solution

Group velocity of localized waves

Not what you're looking for?

Ask Custom Question

Section 2-2 discusses the superposition of two classical sinusoidal waves of slightly different wave numbers k and k+[delta]k to yield a modulated result whose modulations move with a group velocity. A composition almost as simple as the two-component case is the superposition of three waves y_0, y_1, and y_2 with the same total spread [delta]k in wave number (k = 2[pi]/[lambda]);

(see the attachment for the full equations)

The amplitude A/2 of y_1 and y_2 has been chosen to give the superposition the simplest possible form.
y1+y2 can be written as sin A + sin B= 2sin[(A+B)/2]*cos[(A-B)/2], but for y0 how to add them to y0+(y1+y2)?

A) Express the superposition y_0 + y_1 + y_2 as a single product of trigonometric functions. Sketch the resultant wave for t=0.

B) If [delta]k/k = 10^-2, how many zeros does the waveform have within each region of reinforcement (between adjacent zeros of the envelope)?

C) If the phase velocity [omega]/k - 10 cm/sec, [delta]k/k = 10^-2, and [omega][delta]/[omega] = 10^-3, then what is the group velocity of the waveform?

Attachments
Purchase this Solution

Solution Summary

We solve some problems involving the superposition and group velocity of sine waves.

Solution Preview

Please see the attachment.

We are given the following one-dimensional waves:

(a) We wish to express the superposition as a single product of trigonometric functions and to ...

Purchase this Solution


Free BrainMass Quizzes
The Moon

Test your knowledge of moon phases and movement.

Basic Physics

This quiz will test your knowledge about basic Physics.

Intro to the Physics Waves

Some short-answer questions involving the basic vocabulary of string, sound, and water waves.

Introduction to Nanotechnology/Nanomaterials

This quiz is for any area of science. Test yourself to see what knowledge of nanotechnology you have. This content will also make you familiar with basic concepts of nanotechnology.

Classical Mechanics

This quiz is designed to test and improve your knowledge on Classical Mechanics.