Question

Two asteroid s are drifting away from each other.One asteroid have mass of 240000 kg. and the other has a mass of 100000 kg. What is the change in gravitational potential energy as their center s of the mass move from 100 m apart to 1000 m apart?

Answer 1

$\Delta U=Gm_1m_2(\frac 1{r_2}-\frac 1{r_1})=-14.4~mJ.$