# Fixed-end reflection

When the right-end of a rope is fixed somewhere and you hold its left end, let us think of snapping the hand. Then, one pulse transmits from the left end to the right. When the pulse reaches at the right end, which is the fixed-end, the pulse is reflected at that end. Let us take a look at an animation of such reflection. In this video, the right end of the rope is at the x-coordinate of 50 on the horizontal axis.

Because the right end of the rope is fixed, it is called the “fixed end.” At the fixed end, the displacement of the end point is always 0. The pulse is inversed, so that the displacement of each part of the rope becomes negative after the reflection.

In fact, the video clip above is very similar to one below; the left half of the two videos are exactly the same.

The next video clip shows three cycles of a sinusoidal wave traveling from left to right. This wave is also inversed at the fixed end on the right. We can observe the original and the reflected waves are superimposed one on the other.

The video clip above is also exactly the same as the left half of the one below.

So far, the animations were all about transverse waves. Now, let us take a look at the following videos of longitudinal waves with the fixed end reflection. In these videos, a multiple spring-mass system is applied.

The next video is the slow motion version.