Q:  What is the final KE of star A, plus the GPE
            of A-and-black-hole?


          KE_A  =  0.5 * ( 5.97 x 10^(30) kg ) * ( 1.72 x 10^6 m/s )^2

                =  8.83 x 10^(42) J


                        G * M_A * M_BH
          GPE   =   -  --------------------
                         4.49 x 10^(13) m


                =   -  1.76 x 10^(43) J



    Q:  How much KE does star B have in the final state?


          KE_B  =   (initial total energy)  -  ( final KE_A  +  final_GPE )

                =   ( - 2.85 x 10^(40) J )  -  (  - 8.83 x 10^(42) J  )

                =   8.80 x 10^(42) J




    Q:  How fast is star B moving?

      
             0.5 * M_B * (v_B)^2  =  8.80 x 10^(42)  J

                                (   2 * 8.80 x 10^(42) J  )
                    v_B  =  sqrt(  ---------------------  )
                                (     1.99 x 10^(30) J    )


                         =  2.97 x 10^6  m/s   =  2,970 km/s