英语翻译Wave speed in a mediumThe speed of a mechanical wave is

英语翻译Wave speed in a mediumThe speed of a mechanical wave is constant in a given ,medium .The speed depends only on the properties of that medium .If the frequency of a wave in a given medium is changed ,then the wavelength is changed .Figure 15-7 shows two waves produced at different times in the same medium.The wavelengths and the frequencies of the waves are different .