Answer
The initial kinetic energy should be $~~6.9\times 10^7~J$
Work Step by Step
We can use conservation of energy to find the required initial kinetic energy:
$U_1+K_1 = U_2+K_2$
$U_1+K_1 = U_2+0$
$K_1 = U_2-U_1$
$K_1 = -\frac{(6.67\times 10^{-11}~N~m^2/kg^2)(5.0\times 10^{23}~kg)(10~kg)}{8.0\times 10^6~m}+\frac{(6.67\times 10^{-11}~N~m^2/kg^2)(5.0\times 10^{23}~kg)(10~kg)}{3.0\times 10^6~m}$
$K_1 = 6.9\times 10^7~J$
The initial kinetic energy should be $~~6.9\times 10^7~J$
