In physics and engineering, in particular fluid dynamics and hydrometry, the volumetric flow rate, (also known as volume flow rate, rate of fluid flow or volume velocity) is the volume of fluid which passes per unit time; usually represented by the symbol Q (sometimes VÌ). The SI unit is m3/s (cubic metres per second).
The symptoms of the disease were black and purple spots on the body. The spots soon began to become enlarged and swollen. The victims were taken captive by death in about two to seven days. The plague lasted for four years, but it still remained a recurrent fear until the seventeenth century.
The Black Death, or The Black Plague, was one of the most deadly pandemics in human history. It probably began in Central Asia and spread to Europe by the late 1340s. The total number of deaths worldwide from the pandemic is estimated at 75 million people; there were an estimated 20 to 30 million deaths in Europe alone.