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Homework Help: Units in Angular Velocity

  1. Feb 22, 2014 #1
    1. The problem statement, all variables and given/known data
    Hello, I am doing a mechanisms homework assignment in which a hydraulic piston moves out and moves a link connected to the piston in an angular fashion. I'm just a bit confused about the units of angular velocity and I feel very foolish asking this.

    2. Relevant equations
    [tex]\omega \times r = v[/tex]
    [tex]\omega = \frac{v}{r}[/tex]

    3. The attempt at a solution
    [tex] v=0.751751\frac{m}{s} [/tex]
    [tex] r=0.6 m [/tex]
    [tex] \omega=\frac{v}{r}=\frac{0.751751 \frac{m}{s}}{0.6 m} = 1.25 \frac{rad}{s} [/tex]

    Can someone just double check that the units are indeed radians per second? SI units for angular velocity is rad/s.. and this is SI. Just want to double check that it's not rev per second. I know, it's foolish. Thanks in advance!
  2. jcsd
  3. Feb 22, 2014 #2


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    Science Advisor
    Homework Helper

    Yes, it's radians/sec. rev/sec differs by a factor of 2pi. To convince yourself, if v=1m/sec and r=1m and the motion is circular then v/r=1/sec but it would take you 2pi seconds to get around the whole circle and make a rev.
    Last edited: Feb 22, 2014
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