4 Traveling Wave Packet

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With the traveling wave packet we see the need for the distinction between phase and group velocities. Focus your eye on the central peak of this packet. Hit run and follow this individual peak (NOT the center of the envelope) carefully. It moves with the phase velocity and you see it gradually moving ahead, away from the center of the envelope of the packet. Let the packet run for several round trips through the boundaries and check the graph. (Use the speed slider to make it go faster.) From the time for a round trip you can determine the group velocity.