outK v 0 A force applied … < , A simple machine uses a single applied force to do work against a single load force. This is a collection of geometric techniques for the mechanical design of linkages, cam and follower mechanisms and gears and gear trains. [21] In each machine, a force [8] For example, Heron of Alexandria (c. 10–75 AD) in his work Mechanics lists five mechanisms that can "set a load in motion"; lever, windlass, pulley, wedge, and screw,[14] and describes their fabrication and uses. F ideal is the power lost to friction, from conservation of energy, The mechanical efficiency By the late 1800s, Franz Reuleaux[12] had identified hundreds of machine elements, calling them simple machines. 1 < η F {\displaystyle P_{\text{fric}}\,} During the Renaissance the dynamics of the Mechanical Powers, as the simple machines were called, began to be studied from the standpoint of how far they could lift a load, in addition to the force they could apply, leading eventually to the new concept of mechanical work. Therefore, So the mechanical advantage of an ideal machine For example, if the load force on a lever is high enough, the lever will move backwards, moving the input arm backwards against the input force. < {\displaystyle \eta =W_{\text{load}}/W_{\text{1,2}}<1/2\,}, When the machine moves backward from point 2 to point 1 with the load force doing work on the input force, the work lost to friction [18], The classic rules of sliding friction in machines were discovered by Leonardo da Vinci (1452–1519), but were unpublished and merely documented in his notebooks, and were based on pre-Newtonian science such as believing friction was an ethereal fluid. Inclined plane. in v that can be calculated from the machine's geometry and friction. [22] Although some machines only change the direction of the force, such as a stationary pulley, most machines multiply the magnitude of the force by a factor, the mechanical advantage. Wheel & Axle. [10][11] The mechanical advantage of a compound machine is just the product of the mechanical advantages of the simple machines of which it is composed.