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.
How the Black Death Came to an End. During the Middle Ages, the Black Death ravaged Europe and left nearly a third of the population dead. The epidemic reached its zenith in the years 1348 to 1350, though the disease never vanished entirely. It is widely believed that the cause of the Black Death was bubonic plague, an infectious and fatal illness spread by rodents and the fleas infesting them.