Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Radian per second
Summary
The radian per second (symbol: rad⋅s−1 or rad/s) is the unit of angular velocity in the International System of Units (SI). The radian per second is also the SI unit of angular frequency (symbol ω, omega). The radian per second is defined as the angular frequency that results in the angular displacement increasing by one radian every second.
A frequency of one hertz (1 Hz), or one cycle per second (1 cps), corresponds to an angular frequency of 2pi radians per second. This is because one cycle of rotation corresponds to an angular rotation of 2pi radians.
Since the radian is a dimensionless unit in the SI, the radian per second is dimensionally equivalent to the hertz—both can be expressed as reciprocal seconds, s−1. So, context is necessary to specify which kind of quantity is being expressed, angular frequency or ordinary frequency.
One radian per second also corresponds to about 9.55 revolutions per minute. Degrees per second may also be defined, based on degree of arc.
{| class="wikitable"
|+ Quantity correspondence
|-
! Angular frequency !! Frequency
|-
|| 2π rad/s ||1 Hz
|-
|| 1 rad/s || ≈ 0.159155 Hz
|-
|| 1 rad/s || ≈ 9.5493 rpm
|-
|| 0.1047 rad/s || ≈ 1 rpm
|-
|}
A use of the unit radian per second is in calculation of the power transmitted by a shaft. In the International System of Quantities (SI) and the International System of Units, widely used in physics and engineering, the power p is equal to the rotational speed ω multiplied by the torque τ applied to the shaft: p = ω ⋅ τ. When coherent units are used for these quantities, which are respectively the watt, the radian per second, and the newton-metre, and thus W = rad/s × N·m, no numerical factor needed when performing the numerical calculation. When the units are not coherent (e.g. horsepower, turn/min, and pound-foot), an additional factor will generally be necessary.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Related courses (1)
PHYS-201(a): General physics : electromagnetism
Le cours traite des concepts de l'électromagnétisme et des ondes électromagnétiques.