Since energy is conserved (the gravitational force is conservative), we can use the work/energy equation to determine the speed of the satellite as a function of the distance R from O to P. Since the ...

Conservation of momentum explains why a gun or cannon recoils backwards when it is fired. When a cannon is fired, the cannon ball gains forward momentum and the cannon gains backward momentum.

Because momentum is conserved, total momentum afterwards = 60,000 kg m/s.