Is there proof gravity can not be a energy source?

[Omnibus]

Hi utilitarian, you are perfectly right. There is no CoE violation in a closed loop or in any path in a closed sytem in which the start and end points are at same potential.

Now a question remains. When the car is down the hill and the driver brakes and stops the car, the potential energy it had at the start point, has been converted in heat, finally radiated in the environment.
"Potential" energy doesn't mean "fictive" energy. The potential energy was real because the car used it. Thus the question is: where was stored the potential energy of the car at its start point? The only plausible answer is "in the gravity field of massive bodies" (car and earth). When the car is down the hill, the gravity field pattern has changed, resulting in less energy in the field.
The energy density of a gravity field, which can be calculated like the energy density of an electric field (1/2*epsilon0*E²) is g²/(8*pi*G), which is an enormous quantity. Its order of magnitude seems to be rather compatible with the weak change of the gravity field due to the "fall" of the car and supposedly equal to the difference of potential energy of the car between start and arrival points. By modeling the car as a sphere, adding its own gravity field to that of the earth in order to obtain the exact g field, and integrating the density energy all over the space, we should retrieve the potential energy that the car used (I think I could do that, but it is a bit tedious...    ).

@utilitarian is not perfectly right and I explained why. While it is true that there is no violation of CoE in a closed loop (has to be closed loop, not any path) in which the start and the end points are at the same potential, there is a violation of CoE if in addition to potential energy there is kinetic energy imparted as in the case with the car at hand. Kinetic energy imparted to the car when at the top has nothing to do with gravitational potential energy. That kinetic energy is in addition to the potential energy the car has there, as I already expleained. Also, that kinetic energy is a different kinetic energy from the kinetic energy the car has when spontaneously reaches the foot of the hill afte being at rest at the top, as I clearly explained earlier.

As far as storing the potential energy in the gravity field, changing the pattern of gravity field and spending it when car is back, all that is complete nonsense and need not be commented at all.

[spinn_MP]

Lol!

[Omnibus]

The argument I'm providing should be looked into carefully. Spamming by elements such as @spinn_MP doesn't count as an argument.

[spinn_MP]

The argument I'm providing should be looked into carefully.

Spamming by elements such as @spinn_MP doesn't count as an argument.

Rotfl.

Yep, the great OmniBot retard...

[Omnibus]

Hope Stefan follows this exchange and can do something about curbing the spam by @spinn_MB.