Mass Flow Rate

Let's also talk about the mass flow rate or m dot, okay? So, if you look at it, this is expressed as density times velocity—not volume—times the area, okay? So, remember though, there's an assumption over here. The assumption is that we have a uniform flow. If we don't, we have to deal with this rho V dA integration business, okay? And the unit of this is kilogram per second—you can imagine it's mass flow rate—or in the British gravitational, the units of mass is slug per each second. You can also relate the—if you know this V times A is the volumetric flow rate, so you can get a relationship between the mass flow rate is equal to volumetric flow rate times the density. Sometimes this comes in handy.