Chapter 2.4, Problem 172E

As the rocket travels away from Earth’s surface, there is a distance D where the rocket sheds some of its mass, since it no longer needs the excess fuel storage. We can write this function as $F\left(d\right)=\{\begin{array}{l}-\frac{m_{1}k}{d^2}ifd<D\\ -\frac{m_{2}k}{d^2}ifd\ge D\end{array}$ . Is there a D value such that this function is continuous, assuming $m_1\ne m_2$ ?