Q:  What is the gravitational potential energy lost as the
          book falls to the event horizon?

          Express your answer in Joules.


                             G * M * m
            GPE lost  =     ------------
                                R

                           (6.67 x 10^(-11) N*m^2/kg^2) * (2 x 10^(36) kg) * (1 kg)
                      =    -------------------------------------------------------
                                         3 x 10^(9) m


                       =   4.5 x 10^(16)  Joules




          Express your answer in kiloTons of TNT (1 kTon = 4 x 10^(12) Joules)



             GPE lost   =   4.5 x 10^(16) Joules /  4 x 10^(12) Joules/kTon


                        =~     10,000 kTon