| inverse second | |
|---|---|
| Unit system | SI |
| Unit of | frequency |
| Symbol | s−1 |
| Conversions | |
| 1 s−1in ... | ... is equal to ... |
| SI units | 1 Hz |
Theinverse second orreciprocal second (s−1), also calledper second, is aunit defined as themultiplicative inverse of thesecond (a unit oftime). It is applicable forphysical quantities ofdimensionreciprocal time, such asfrequency andstrain rate.
It isdimensionally equivalent to:
However, the special names and symbols above for s−1 are recommend for clarity.[a][b]
Reciprocal second should not be confused withradian per second (rad⋅s−1), the SI unit forangular frequency andangular velocity. As theradian is adimensionless unit, radian per second is dimensionally consistent with reciprocal second. However, they are used for differentkinds of quantity, frequency and angular frequency, whose numerical value differs by 2π.
Theinverse minute orreciprocal minute (min−1), also calledper minute, is 60−1 s−1, as 1 min = 60 s; it is used in quantities of type "counts per minute", such as:
Inverse square second (s−2) is involved in the units of linearacceleration,angular acceleration, androtational acceleration.