Why in a gravity field the potential energy is not defined as equal to the kinetic energy?

Question

Does Law of Conservation of energy applies?

Answer 1

hmm
is the question is clear in itself?
if u have to park satellite in certain orbit, then u must give kinetic energy to it so that it would rise to that height and acquire the same Potential energy.

Answer 2

Well, potential energy is just that...potential. Specifically, the graviational potential energy is between two massive objects can be calculated according to Newton's law (or Einstein's if you need _really_ high accuracy).

Kinetic energy is due solely to motion. If it ain't movin', there's no kinetic energy.

If you let one of the masses go, then the gravitiational potential energy becomes kinetic energy of the moving mass. Conservation of energy for this system simply means that the moving mass will convert, at most, all the gravitational potential energy to kinetic energy.

Bottom line, potential energy and kinetic energy are two _different_ measures of the energy of a system - they can be converted one into the other and the total will never be more or less than what you started with.