Reflection of a Pulse from Fixed and Free Ends, Grade 10 Physics Let us now consider what happens to a pulse when it reaches the end of a medium. The medium can be fixed, like a rope tied to a wall, or it can be free, like a rope tied loosely to a pole. 1/ Reflection of a Pulse from a Fixed End Activity :: Investigation : Reflection of a Pulse from a Fixed End Tie a rope to a wall or some other object that cannot move. Create a pulse in the rope by flicking one end up and down. Observe what happens to the pulse when it reaches the wall. When the end of the medium is fixed, for example a rope tied to a wall, a pulse reflects from the fixed end, but the pulse is inverted (i.e. it is upside-down). This is shown in Figure 5.9. 2/ Reflection of a Pulse from a Free End Activity :: Investigation : Reflection of a Pulse from a Free End Tie a rope to a pole in such a way that the rope can move up and down the pole. Create a pulse in the rope by flicking one end up and down. Observe what happens to the pulse when it reaches the pole. When the end of the medium is free, for example a rope tied loosely to a pole, a pulse reflects from the free end, but the pulse is not inverted. This is shown in Figure 5.10. We draw the free end as a ring around the pole. The ring will move up and down the pole, while the pulse is reflected away from the pole. Important: The fixed and free ends that were discussed in this section are examples of boundary conditions. You will see more of boundary conditions as you progress in the Physics syllabus. Exercise: Pulses at a Boundary II E - 1. A rope is tied to a tree and a single pulse is generated. What happens to the pulse as it reaches the tree? Draw a diagram to explain what happens. E - 2. A rope is tied to a ring that is loosely fitted around a pole. A single pulse is sent along the rope. What will happen to the pulse as it reaches the pole? Draw a diagram to explain your answer. Xem thêm: Physics 10.IV Transverse Pulses High School Students Studying the Sciences Physics