Issue about the velocity/potential energy of satellites (1 Viewer)

[Everwinter]

In the calculation of the velocity or potential energy of LEO and geostationary satellite, with v = √GM/r or U = -GMm/r, many textbook solutions only consider the amplitude of the satellite as r, instead of the sum of Earth orbit and the amplitude. Is this considered as an acceptable solution in HSC? Would I be wrong if I use the sum of Earth orbit and the amplitude for r?

 

[tito981]

You are meant to use the sum of altitude and radius of earth.