Hertz radians per second. Thus a disc rotating at 60 revolutions per minute (rpm) is said to be rotating at either 2 rad/s "or" 1 Hz, where the former measures the angular velocity and the latter reflects the number of "complete" revolutions per second. The conversion between a frequency "f" measured in hertz and an angular velocity "ω" measured in radians per second is The hertz is named after the German physicist Heinrich Hertz (1857–1894), who made important scientific contributions to the study of electromagnetism. The name was established by the International Electrotechnical Commission (IEC) in 1930. It was adopted by
Cubic metre per second Cubic metre per second A cubic metre per second (ms, m/s, cumecs or cubic meter per second in American English) is a derived SI unit of volumetric flow rate equal to that of a stere or cube with sides of one metre (~39.37 in) in length exchanged or moving each second. It is popularly used for water flow, especially in rivers and streams, and fractions for HVAC values measuring air flow. The term cumec is also used, as shorthand for "Cubic metres per second", with the plural form "cumecs" also common in speech. It is commonly used between workers in