&gt; &gt; This means that, if you follow the rules of the SI, 1 Hz = 1&#x2F;s = 1 radian&#x2F;s<p>&gt; I fail to see how this follows from the SI definition of either the hertz or the radian.<p>The <i>definition</i> of &#x27;Hertz&#x27; is 1&#x2F;s.  &#x27;Radian&#x27; is not a unit, but a dimensionless number (the number 1, in fact, representing the ratio of arclength to radius where the arclength and radius happen to be the same), so that 1&#x2F;s = radian&#x2F;s.