Verge escapement verge escapement mechanism was applied to tower clocks, creating the first mechanical clock. In spite of the fact that these clocks were celebrated objects of civic pride which were written about at the time, it may never be known when the new escapement was first used. This is because it has proven difficult to distinguish from the meager written documentation which of these early tower clocks were mechanical, and which were water clocks; the same Latin word, "horologe", was used for both. None of the original mechanisms have survived unaltered. Sources differ on which was the first clock 'known' to
Mechanical energy isolated system remains constant in time, as long as the system is free of friction and other non-conservative forces. In any real situation, frictional forces and other non-conservative forces are present, but in many cases their effects on the system are so small that the principle of conservation of mechanical energy can be used as a fair approximation. Though energy cannot be created or destroyed in an isolated system, it can be converted to another form of energy. In a mechanical system like a swinging pendulum subjected to the conservative gravitational force where frictional forces like air drag and friction