g A slurry enters a filtertation system in which the cross-sectional area 0.18 m2, the thickness of the cake is currently 0.1 m, the density of the solid particulates in 2,294 kg/m3 and the density of the fluid 1020 kg/m3. The porosity of the cake is 0.32. If 1.6 m3 of filtrate is collected what is the inlet slurry concentration (in kg/m3)?

It is increased due to the doppler effect. (apex)

Sounds propagates through some kind of medium. usually it's air, but it goes just as well through solid objects like walls, windows etc. a soundwave will compress the (air)molecules in front of it, and if this increased density wave hits your ears, you register it as sound. solid objects like walls are a lot denser than air, this means that they will damp a wave, but also carry it easier.