When a workman hammers to one end of the long iron pipeline, an observer places his ear on the other end of pipeline. How he can distinctly hear two sounds? Justify your answer.
Due to propagation of sound through solids such as iron, the sound of hammering to one end will be heard by the observer in the other end of the pipeline. Also, the sound of hammering will be propagated through air to reach the observer. As we know that, sound travels fester in iron than in air. So, the observer hear two sounds. The first one, travelling through the iron pipeline and the second travelling through air.