Rayleigh group velocity

例句：

1. 1. The wavepropagates through the medium at aspeed that is determined by the properties ofthe medium.
   波通过介质传播的速度取决于介质的性质。
2. 2. In this experiment, we will measurethe speed of sound in different materials.
   在这个实验中，我们将测量不同材料中声速的速度。
3. 3. The speed of light in vacuumis approximately 299,792 kilometers per second.
   光在真空中的速度大约是每秒299,792公里。