Escapement may avoid the need for lubrication in the escapement (though it does not obviate the requirement for lubrication of other parts of the gear train). The accuracy of a mechanical clock is dependent on the accuracy of the timing device. If this is a pendulum, then the period of swing of the pendulum determines the accuracy. If the pendulum rod is made of metal it will expand and contract with heat, shortening or lengthening the pendulum; this changes the time taken for a swing. Special alloys are used in expensive pendulum-based clocks to minimize this distortion. The degrees of arc
Mechanical energy steam engine converts heat energy to mechanical energy. Energy is a scalar quantity and the mechanical energy of a system is the sum of the potential energy which is measured by the position of the parts of the system. The kinetic energy which is also called the energy of motion: The potential energy, "U", depends on the position of an object subjected to a conservative force. It is defined as the object's ability to do work and is increased as the object is moved in the opposite direction of the direction of the force. If "F" represents the conservative force