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 was an epidemic outbreak of bubonic plague in Europe around 1348 that killed between one-third and two-thirds of the population in less than five years. The epidemic spanned from China to England to North Africa, transmitted along the Silk Road and other trade routes. Worldwide, the plague may have killed one-quarter of all people. Repeated outbreaks continued in Europe into the 18th century. Some historians believe the drastic reduction in population hurried the end of feudalism by raising the value of labor and the power of workers, as seen in incidents like the 1381 Peasants Revolt in England.