Boys start to get acne at the age of approximately 12 years, with a range of 9 to 15 years old. As most girls will attest, boys on average mature later than girls. Early on in the onset of teen acne, the main lesions are blackheads and whiteheads.
The angular size (angular diameter, apparent size) of an object as seen from a given point is the visual diameter of the object measured as an angle. The visual diameter is the diameter of the perspective projection of the object on a plane through its center that is perpendicular to the viewing direction.
What you have above is the magnitude of the angular velocity (which I am assuming is expressed in radians). $$ \vert \omega \vert = \frac{d \theta}{dt} \mbox{rad} \space s^{-1} $$. Often people leave out the radian, since it's just a number. The radian is engineering-dimensionless.50. Well, the key difference here is that one is a vector quantity while the other is a scalar. If your angle is measured in radians then angular frequency $\omega$ is given by. $$ \omega = 2 \pi f \space \mbox{(rad)} s^{-1} $$.