# Homework Help: Velocity frequency and period

1. Mar 26, 2012

### bfusco

1. The problem statement, all variables and given/known data
im confused on something. if the period is the amount of time to make 1 spin once, and the frequency is the inverse of that, i dont understand how frequency isnt the same thing as centripetal velocity.

2. Mar 26, 2012

### PeterO

I have heard of Centripetal acceleration, but never centripetal velocity??

Do you perhaps mean angular velocity ω - which I have often seen written in radians per second, not (full) cycles per second, so they would vary by a factor of 2∏

3. Mar 26, 2012

### Staff: Mentor

Perhaps because there's no such thing as centripetal velocity?

Are you thinking of angular velocity? The units of that are radians per second. This is not the same thing as cycles per second (frequency), since in rotational motion a "cycle" comprises $2\pi$ radians of angular distance. Thus ω = $2\pi f$.

4. Mar 26, 2012

### bfusco

wait...can angular velocity be calculated in revs/minute, or radians/sec? i thought that the revs/min was "centripetal velocity", and radians/sec was angular velocity

5. Mar 26, 2012

### Staff: Mentor

RPM, RPS, and radians/sec are all measures of angular velocity. They are all related by conversion actors. A "revolution" is $2 \pi$ radians.

6. Mar 26, 2012

### bfusco

oh...didnt know that