Question

The earth's orbital angular speed in rad/s due to its motion around the sun

Answer 1

           (2π rad/year) x (1 yr/365 days) x (1 day / 86,400 seconds)

       =    (2π) / (365 x 86,400)        rad/sec

       =        0.000 000 2  radian/sec

       =          0.2 microrad/sec