If I made a ball roll endlessly in a closed loop, would that be considered a perpetual motion machine?

Not free energy obviously, but perpetual motion?If I made a ball roll endlessly in a closed loop, would that be considered a perpetual motion machine?Only if the ball really continues rolling indefinitetly, without ANY additional energy from external sources, and does not lose any energy.If I made a ball roll endlessly in a closed loop, would that be considered a perpetual motion machine?Yes it would be.

But friction and gravity would slow the ball down therefore not possible.If I made a ball roll endlessly in a closed loop, would that be considered a perpetual motion machine?IF the hypothetical ball rolled endlessly, free from all external forces, such as gravity, radiation, rotational movement of the earth, and so on, then it would, indeed, be perpetual motion. But to be a perpetual motion machine, than work would somehow have to be able to be extracted, and that must require energy to be added to compensate for the energy removed. That compensation also applies to replacing the energy removed by friction and other retarding forces. In short, the energy consumed must be replaced by external energy added, or by the conversion of some of the moving mass to energy. Or so said a little, white haired gentleman, among others.

The goal in machine design is to get as close as possible to having the energy input equal the energy output. In the real world, the best that can be achieved ranges from 20% to 80% energy output as a function of energy input, depending on machine type.

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