机械波图像（Mechanical wave image）.docVIP

机械波图像（Mechanical wave image） First, the formation process and characteristics of waves Each particle has a harmonic motion centered on its equilibrium position, and the vibration of the latter particle always lags behind the vibration of the particle preceding it. Wave propagation is only the form of particle motion and vibration energy, and the particles do not change with the wave in the medium. Example 1: a row of shear waves propagate along the rope to the right. At some point the rope forms a concave and convex shape as shown in figure 1. At this point on the rope A, B, C, D, E, F six particles () A. they have the same amplitude B. particles, D and F, have the same velocity direction C. particles, A and C, have the same velocity direction D. from this point on, the particle B is back to the equilibrium position than C Figure 1 Analysis: when the wave source vibrates, each particle on the rope follows the mutual elastic force to do forced vibration, without considering the energy loss in the propagation, each particle has the same amplitude. The A entry is correct. When the wave propagates, the vibration of a particle far away from the source of wave lags behind the vibration of the particle near the source of the wave, and follows the vibration of the particle near it. As shown by the diagram, the wave source is at the left end, therefore, the D point follows the particle C of the near wave source, and the F point follows the particle E of the near wave source, and the velocity direction is opposite. B entry error. Similarly, at this point, the particle A is moving downward, and the particle C is moving upward, and the velocity direction is opposite. C entry error. As the B and C two particles move upward at this time, the maximum displacement of the C is greater than that of the B, and the C is back to the equilibrium position later than the B, and the D term is correct. Therefore, select the AD item. Example 2: a series of simple harmonic waves propagating al