In physics, a simple machine is any device that only requires the application of a single force to work. Work is done when a force is applied and results in movement over a set distance. The work done is the product of the force and the distance. The amount of work required to achieve a set objective is constant; however the force required can be reduced provided the lesser force is applied over a longer distance. The ratio between the two forces is the mechanical advantage. A typical Internet forum discussion, with common elements such as quotes and spoiler brackets A page from a forum showcasing emoticons and Internet slang An Internet forum is a web application for holding discussions and posting user generated content. ... Simple Machines Forum (abbreviated as SMF) is a freeware Internet forum script. ... A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... For other uses, see Force (disambiguation). ... In physics, mechanical work is the amount of energy transferred by a force. ...

The traditional list of simple machines is:

• The inclined plane
• The wheel and axle
• The lever
• The pulley
• The wedge
• The screw

The ratio of the output force to the input force is the mechanical advantage. For example, the mechanical advantage of a lever is equal to the ratio of its two arms. The mechanical advantage of an inclined plane (with the force acting parallel to the plane) is the cosecant of the angle of inclination. The inclined plane is one of the classical simple machines; as the name suggests, it is a flat surface whose endpoints are at different heights. ... A pair of metal wheels with bearings fitted to cranked axle. ... For the Portuguese town and parish, see Lever, Portugal. ... For the band, see Pulley (band). ... Technically a portable double inclined plane, a wedge is a simple machine used to separate two objects, or portions of objects, through the application of force, perpendicular to the inclined surfaces, developed by conversion of force applied to the wide end. ... Look up screw in Wiktionary, the free dictionary. ... In physics and engineering, mechanical advantage (MA) is the factor by which a mechanism multiplies the force put into it. ... In mathematics, the trigonometric functions are functions of an angle, important when studying triangles and modeling periodic phenomena. ...

Note: Real machines are also affected by factors such as friction and elasticity, so the actual mechanical advantage of a simple machine will usually differ from its theoretical value.

These simple machines fall into two general classes; those dependent on the vector resolution of forces (inclined plane, wedge, screw) and those in which there is an equilibrium of torques (lever, pulley, wheel). Simple machines are often used in combination as components of more complex machines. For example: wheels, axles, levers, and pulleys are all used in the formation of modern bicycles. For other uses, see Friction (disambiguation). ... Elasticity is a branch of physics which studies the properties of elastic materials. ... This article is about vectors that have a particular relation to the spatial coordinates. ... A standard definition of mechanical equilibrium is: A system is in mechanical equilibrium when the sum of the forces, and torque, on each particle of the system is zero. ... For other senses of this word, see torque (disambiguation). ... For other uses, see Bicycle (disambiguation). ...

Variations to the list of simple machines:

• Some say there are only five simple machines, arguing that the wedge is a moving inclined plane.
• Others further simplify the list to four saying that the screw is a helical inclined plane. This position is less accepted because a screw simultaneously converts a rotational force (torque) to a linear force.
• Some go even further to insist that only two simple machines exist, as a pulley and wheel and axle can be viewed as unique forms of levers, leaving only the lever and the inclined plane.[1][2]
• Hydraulic systems can also provide amplification of force but are not included in lists of simple machines.

For other senses of this word, see torque (disambiguation). ... Hydraulics is a branch of science and engineering concerned with the use of liquids to perform mechanical tasks. ...

See also

• Machine
• Invention
• Archimedes' screw