The gravitational potential at a point above the surface of earth is --5.12 × 107 J/kg and the acceleration due to gravity at that point is 6.4 m/s2. Assume that the mean radius of earth to be 6400 km. The height of this point above the earth’s surface is:
1
1600 km
2
540 km
3
1200 km
4
1000 km