Radian per second frequency, , corresponds to an ordinary frequency, , which corresponds to a frequency of rotation of . 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
Unit of length in vacuum during a time interval of seconds." It is approximately equal to . Other units are derived from the metre by adding prefixes from the table below: For example, a kilometre is . In the Centimetre–gram–second system of units, the basic unit of length is the centimetre, or of a metre. Other non-SI units are derived from decimal multiples of the metre. The basic unit of length in the Imperial and U.S. customary systems is the yard, defined as exactly by international treaty in 1959. Common Imperial units and U.S. customary units of length include: In addition, the following