How Does Angular Velocity Relate to Radians and Hertz?

In summary, the conversation discusses the calculation of angular velocity (\omega) using the given values for velocity (v) and radius (r). The resulting value is expressed in seconds (s), but since angular velocity is typically measured in radians per second (rad/s), the question arises on how to convert the units. It is then clarified that radians are dimensionless, making rad/s equivalent to 1/s or Hertz (Hz), the unit of frequency.
  • #1
tony873004
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velocity = 0.5 m/s
radius = 1 m

[tex]\omega = \frac{v}{r}[/tex]

[tex]\omega = \frac{0.5 m/s}{1 m}[/tex]

the meters cancel and I'm left with

[tex]\omega = 0.5 s[/tex]

But [tex]\omega[/tex] is supposed to be expressed in radians/s

How do I get those output units with the given input units?
 
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  • #2
Why do you have "w = 0.5s" when your calculations suggest it should be "w = 0.5/s = 0.5 Hz"? Note that radians are dimensionless, so rad/s is equivalent to 1/s, or Hz.
 
  • #3
AKG said:
Why do you have "w = 0.5s" when your calculations suggest it should be "w = 0.5/s = 0.5 Hz"? Note that radians are dimensionless, so rad/s is equivalent to 1/s, or Hz.

Hertz (Hz) is the unit of frequency, and the unit of angular velocity is rad/s. Both frequency and angular velocity have the dimension of 1/[time], so they can be written also as 1/s.

See http://physics.nist.gov/cuu/Units/units.html

ehild
 

Related to How Does Angular Velocity Relate to Radians and Hertz?

1. What is angular speed?

Angular speed is a measure of how fast an object is rotating around a fixed point. It is usually measured in radians per second (rad/s) or degrees per second (deg/s).

2. How is angular speed different from linear speed?

Angular speed is a measure of how fast an object is rotating, while linear speed is a measure of how fast an object is moving in a straight line. Angular speed is measured in units of rotation, while linear speed is measured in units of distance.

3. What are the common units of angular speed?

The most common units of angular speed are radians per second (rad/s) and degrees per second (deg/s). However, other units such as revolutions per minute (rpm) or cycles per second (cps) are also sometimes used.

4. How is angular speed related to angular velocity?

Angular speed and angular velocity are closely related, but not the same. Angular speed is the magnitude of angular velocity, which also takes into account the direction of rotation.

5. Can angular speed be negative?

Yes, angular speed can be negative. This indicates that the object is rotating in the opposite direction compared to a positive angular speed. In most cases, the direction of rotation is indicated by the sign of the angular speed.

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