Radian per second Radian per second The radian per second (symbol: rad·s or rad/s) is the SI unit of rotational speed (angular velocity), commonly denoted by the Greek letter "ω" (omega). The radian per second is also the unit of angular frequency. The radian per second is defined as the change in the orientation of an object, in radians, every second. Since the radian is a dimensionless unit, the radian per second is dimensionally equivalent to the hertz—both are defined as s. This may lead to confusion between the quantities angular frequency "ω" and frequency "ν". A use of the "unit radian per
Hartley (unit) digit, a ban corresponds to a decimal digit. A deciban is one tenth of a ban; the name is formed from "ban" by the SI prefix "deci-". One hartley corresponds to log(10) bit = ln(10) nat, or approximately 3.322 Sh, or 2.303 nat. A deciban is about 0.332 Sh. Though not an SI unit, the hartley is part of the International System of Quantities, defined by International Standard IEC 80000-13 of the International Electrotechnical Commission. It is named after Ralph Hartley. The term "hartley" is named after Ralph Hartley, who suggested in 1928 to measure information using a logarithmic base