From Wikipedia, the free encyclopedia
A unit of frequency
The
inverse second
or
reciprocal second
(
s
?1
), also called
per second
, is a
unit
defined as the
multiplicative inverse
of the
second
(a unit of
time
). It is applicable for
physical quantities
of
dimension
reciprocal time
, such as
frequency
and
strain rate
.
It is
dimensionally
equivalent to:
However, the special names and symbols above for s
?1
are recommend for clarity.
[a]
[b]
Reciprocal second should not be confused with
radian per second
(rad?s
?1
), the SI unit for
angular frequency
and
angular velocity
. As the
radian
is a
dimensionless unit
, radian per second is dimensionally consistent with reciprocal second. However, they are used for different
kinds of quantity
, frequency and angular frequency, whose numerical value differs by 2
π
.
The
inverse minute
or
reciprocal minute
(
min
?1
), also called
per 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 linear
acceleration
,
angular acceleration
, and
rotational acceleration
.
See also
[
edit
]
Notes
[
edit
]
- ^
"The SI unit of frequency is given as the hertz, implying the unit cycles per second; the SI unit of angular velocity is given as the radian per second; and the SI unit of activity is designated the becquerel, implying the unit counts per second. Although it would be formally correct to write all three of these units as the reciprocal second, the use of the different names emphasises the different nature of the quantities concerned."
[1]
- ^
"(d) The hertz is used only for periodic phenomena, and the becquerel (Bq) is used only for stochastic processes in activity referred to a radionuclide."
[2]
References
[
edit
]