Anchor escapement to only 4°-6°. In addition to the improved accuracy due to isochronism, this allowed clocks to use longer pendulums, which had a slower 'beat'. Lower air drag meant they needed less power to keep swinging, and caused less wear on the clock's movement. The anchor also allowed the use of a heavier pendulum bob for a given drive force, making the pendulum more independent of the escapement (higher Q), and thus more accurate. These long pendulums required long narrow clock cases. Around 1680 British clockmaker William Clement began selling the first commercial clocks to use the anchor escapement, tall freestanding
Mechanical energy at the pivot are negligible, energy passes back and forth between kinetic and potential energy but never leaves the system. The pendulum reaches greatest kinetic energy and least potential energy when in the vertical position, because it will have the greatest speed and be nearest the Earth at this point. On the other hand, it will have its least kinetic energy and greatest potential energy at the extreme positions of its swing, because it has zero speed and is farthest from Earth at these points. However, when taking the frictional forces into account, the system loses mechanical energy with each