What is the angular velocity of the Earth? 

                2 pi radians
      omega  =  ------------  =  7.2722052166  x  10^(-5) rad/s
                  86,400 s



 What is the rotational kinetic energy of the Earth? 


      KE     =  (1/2) * I * omega^2

             =  (1/2) * 9.7 x 10^(37) kg * [ 7.2722052166 x 10^(-5) rad/s ]^2

             =  2.564920982579  x 10^(29)  J



   Write an equation for the new angular velocity of the Earth
           in terms of the other quantities.

                              ( 2 * (KE - Eus) )
            omega_new  =  sqrt( -------------- )
                              (       I        )




  Compute the new angular velocity omega_new.


            omega      =   7.2722052166  x  10^(-5) rad/s
            omega_new  =   7.2722052152  x  10^(-5) rad/s

          --------------------------------------------------

            change     =   0.0000000014  x  10^(-5) rad/s

                       =   1.4 x 10^(-14) rad/s



  How long would the new period of the Earth's rotation be?

                     2 * pi rad 
         P_new  =   ------------  =  86400.000017  sec
                      omega_new


                =    17 microseconds longer than the current period



  Suppose we could generate energy in this way.
            Roughly how long could we continue to power the
            US before the length of the day increased by one second?


         If the period kept increasing by 17 microseconds each year,
         it would take around 60,000 years for the Earth's rotation
         to increase by one second.