Lateral longitudinal waves

Similarly, the contribution to the response in the microscope due to lateral longitudinal waves is, by analogy with (7.42),... 

An experimental V(z) curve measured on PMMA is given in Fig. 7.7. The oscillations are entirely due to lateral longitudinal waves. At 225 MHz, eqn (7.54) would predict a periodicity of 20 m this can be compared with the spacing of the oscillations in the measured data. 

In isotropic solids one can distinguish longitudinal waves and shear waves. When the lateral dimensions are much less than the wavelength (threads) an extensional wave is propagated. 

In threads or filaments, where the lateral dimensions are much smaller than the wave-length, the longitudinal wave is almost purely extensional its speed is given by the expression... 

Once the gas mass quicldy flowed out of the seawater into the sky, the seawater would rebound back. So, a huge volume of seawater could be displaced and moved laterally and returned back quickly. A huge volumetric movement of the thick seawater can be propagated laterally in longitudinal wave form to far distance, which eventually caused the tsunamis when the waves reached shorelines. 

In the mind of de Broglie, the wave accompanies the particle. He also talked about a pilot wave that guided the particle in its path. It is unclear in the theory of de Broglie what the physical meaning of the matter wave is. Is it a longitudinal wave like sound waves How then could waves appear in a vacuum The meaning of the waves was not cleared up until the interpretation of Max Born some years later. 

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