Editing Simple machine (section)

{{short description|Mechanical device that changes the direction or magnitude of a force}}
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{{Use mdy dates|date=November 2022}}[[File:Six Mechanical Powers.png|thumb|250x250px|The six classical simple machines]]
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A '''simple machine''' is a [[machine|mechanical device]] that changes the [[Direction (geometry) |direction]] or [[Magnitude_(mathematics) |magnitude]] of a [[force]].<ref name="Paul-Roy-Mukherjee-2005">{{Citation |last1=Paul |first1=Akshoy |last2=Roy |first2=Pijush |last3=Mukherjee |first3=Sanchayan |title=Mechanical sciences: engineering mechanics and strength of materials |year=2005 |publisher=Prentice Hall of India |isbn=978-81-203-2611-8 |page=215 |postscript=.}}</ref> In general, they can be defined as the simplest [[Mechanism (engineering) |mechanism]]s that use [[mechanical advantage]] (also called leverage) to multiply force.<ref name="Asimov1988">{{Citation |last=Asimov |first=Isaac |title=Understanding Physics |year=1988 |publisher=Barnes & Noble |location=New York |isbn=978-0-88029-251-1 |url=https://books.google.com/books?id=pSKvaLV6zkcC&q=Asimov+simple+machine&pg=PA88 |page=88 |postscript=.}}</ref> Usually the term refers to the six classical simple machines that were defined by [[Renaissance]] scientists:<ref name="Anderson">{{cite book
  |last=Anderson
  |first=William Ballantyne
  |title=Physics for Technical Students: Mechanics and Heat
  |year=1914
  |publisher=McGraw Hill
  |location=New York
  |url=https://archive.org/details/bub_gb_Pa0IAAAAIAAJ/page/n131
  |access-date=2008-05-11
  |pages=112}}</ref><ref name="Britannica1773">{{cite encyclopedia
  | title = Mechanics
  | encyclopedia = Encyclopædia Britannica
  | volume = 3
  | pages = 44
  | publisher = John Donaldson
  | date =1773
  | url = https://books.google.com/books?id=Ow8UAAAAQAAJ&q=%22simple+machine%22+%22mechanical+powers%22+lever+screw+inclined+plane+wedge+wheel+pulley&pg=PA44
  | access-date = 5 April 2020}}</ref><ref name="Morris">{{cite book
 | last1  = Morris
 | first1 = Christopher G.
 | title  = Academic Press Dictionary of Science and Technology
 | publisher = Gulf Professional Publishing
 | date   = 1992
 | pages  = 1993
 | url    = https://books.google.com/books?id=nauWlPTBcjIC&q=%22simple+machine%22&pg=PA1993
 | isbn   = 978-0122004001
 }}</ref>
* [[Lever]]
* [[Wheel and axle]]
* [[Pulley]]
* [[Inclined plane]]
* [[Wedge (mechanical device)|Wedge]]
* [[Screw (simple machine)|Screw]]
A simple machine uses a single applied force to do [[Mechanical work|work]] against a single load force. Ignoring [[friction]] losses, the work done on the load is equal to the work done by the applied force. The machine can increase the amount of the output force, at the cost of a proportional decrease in the distance moved by the load. The ratio of the output to the applied force is called the ''mechanical advantage''.

Simple machines can be regarded as the elementary "building blocks" of which all more complicated [[machine]]s (sometimes called "compound machines"<ref name="U_Virginia_elementary_curriculum">{{Citation|url=http://galileo.phys.virginia.edu/outreach/8thgradesol/compoundmachine.htm | title=Compound machines|publisher=University of Virginia Physics Department|access-date=2010-06-11|postscript=.}}</ref><ref name="Usher">{{cite book|last=Usher|first=Abbott Payson |title=A History of Mechanical Inventions|publisher=Courier Dover Publications|year=1988|location=US|pages=98 | url=https://books.google.com/books?id=xuDDqqa8FlwC&q=wedge+and+screw&pg=PA196 |isbn=978-0-486-25593-4}}</ref>) are composed.<ref name="Asimov1988"/><ref>{{cite conference  |last=Wallenstein  |first=Andrew  |title=Foundations of cognitive support: Toward abstract patterns of usefulness  |date=June 2002  |book-title=Proceedings of the 9th Annual Workshop on the Design, Specification, and Verification of Interactive Systems  |publisher=Springer  |url=https://books.google.com/books?id=G9sZf7D24a8C&q=simple+machines&pg=PA136  |access-date=2008-05-21  |page=136|isbn=978-3540002666 }}</ref> For example, wheels, levers, and pulleys are all used in the mechanism of a [[bicycle]].<ref name="Prater1994">{{Citation|last=Prater|first=Edward L.|year=1994|title=Basic machines | url=http://www.constructionknowledge.net/public_domain_documents/Div_1_General/Basic_Skills/Basic%20Machines%20NAVEDTRA%2014037%201994.pdf |publisher=U.S. Navy Naval Education and Training Professional Development and Technology Center, NAVEDTRA 14037|postscript=.}}</ref><ref name="USBureauNavalPersonnel1971">{{Citation|author=U.S. Navy Bureau of Naval Personnel|year=1971| url=http://www.webpal.org/SAFE/aaarecovery/5_simple_technology/basic_machines.pdf | title=Basic machines and how they work|publisher=Dover Publications|postscript=.}}</ref> The mechanical advantage of a compound machine is just the product of the mechanical advantages of the simple machines of which it is composed.

Although they continue to be of great importance in mechanics and applied science, modern mechanics has moved beyond the view of the simple machines as the ultimate building blocks of which all [[machine (mechanical)|machines]] are composed, which arose in the Renaissance as a [[neoclassicism|neoclassical]] amplification of [[ancient Greece|ancient Greek]] texts. The great variety and sophistication of modern machine linkages, which arose during the [[Industrial Revolution]], is inadequately described by these six simple categories. Various post-Renaissance authors have compiled expanded lists of "simple machines", often using terms like ''basic machines'',<ref name="Prater1994"/> ''compound machines'',<ref name="U_Virginia_elementary_curriculum"/> or ''machine elements'' to distinguish them from the classical simple machines above. By the late 1800s, [[Franz Reuleaux]]<ref name="Reuleaux1876">{{Citation |last=Reuleaux |first=F. |orig-year=1876 |year=1963 |title=The kinematics of machinery (translated and annotated by A.B.W. Kennedy) |publisher=reprinted by Dover |location=New York |postscript=.}}</ref> had identified hundreds of machine elements, calling them ''simple machines''.<ref name="KMODDL">{{Citation |author=Cornell University |author-link=Cornell University |title=Reuleaux Collection of Mechanisms and Machines at Cornell University |url=http://kmoddl.library.cornell.edu/rx_collection.php |publisher=Cornell University |postscript=.}}</ref> Modern machine theory analyzes machines as [[kinematic chain]]s composed of elementary linkages called [[kinematic pair]]s.