Skip to ContentGo to accessibility page
OpenStax Logo
Physics

Key Terms

PhysicsKey Terms

Key Terms

complex machine
a machine that combines two or more simple machines
efficiency
output work divided by input work
energy
the ability to do work
gravitational potential energy
energy acquired by doing work against gravity
ideal mechanical advantage
the mechanical advantage of an idealized machine that loses no energy to friction
inclined plane
a simple machine consisting of a slope
input work
effort force multiplied by the distance over which it is applied
joule
the metric unit for work and energy; equal to 1 newton meter (N∙m)
kinetic energy
energy of motion
law of conservation of energy
states that energy is neither created nor destroyed
lever
a simple machine consisting of a rigid arm that pivots on a fulcrum
mechanical advantage
the number of times the input force is multiplied
mechanical energy
kinetic or potential energy
output work
output force multiplied by the distance over which it acts
potential energy
stored energy
power
the rate at which work is done
pulley
a simple machine consisting of a rope that passes over one or more grooved wheels
screw
a simple machine consisting of a spiral inclined plane
simple machine
a machine that makes work easier by changing the amount or direction of force required to move an object
watt
the metric unit of power; equivalent to joules per second
wedge
a simple machine consisting of two back-to-back inclined planes
wheel and axle
a simple machine consisting of a rod fixed to the center of a wheel
work
force multiplied by distance
work–energy theorem
states that the net work done on a system equals the change in kinetic energy
PreviousNext
Order a print copy
Citation/Attribution
Reuse and redistribution of this content in digital or print format:
  • This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's prior written permission.
  • This book uses the Creative Commons Attribution License, which means that you can reuse and modify the material only for noncommercial purposes, must attribute Texas Education Agency (TEA), and must distribute any derivative works under the same license. The original material is available at: https://www.texasgateway.org/book/tea-physics . Changes were made to the original material, including updates to art, structure, and other content updates.
  • Any commercial printing of this textbook, including using a local or custom printer, must be approved by OpenStax, and proper citation provided.
  • OpenStax-copyrighted images, activities, assessments, and similar components of this book are subject to the same licensing – CC-BY-NC-SA. They can be used for noncommercial purposes with attribution. Commercial use requires permission.
  • Permission requests: Anyone who intends to incorporate this content (including text, images, and other components) into large language models, use it in AI offerings, use it commercially (including in print), and/or has questions about another use case is welcome to complete our reuse request form.
Attribution information
  • If you are redistributing all or part of this book in a noncommercial print format, then you must include on every physical page the following attribution:

    Access for free at https://openstax.org/books/physics/pages/1-introduction

  • If you are redistributing all or part of this book in a noncommercial digital format, then for every page that includes OpenStax content, you must license the derivative work under the same CC-BY-NC-SA license as the original, and include on every digital page view the following attribution:

    Access for free at https://openstax.org/books/physics/pages/1-introduction

Citation information

The information below includes the information needed to generate citations in most major styles (APA, MLA, etc.); you must reformat and organize the information as needed to fit the requirements of the style. Use the information below to generate a citation. We recommend using a citation tool such as this one.

© Jul 8, 2026 Texas Education Agency (TEA). The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo, and Rice University name, and Rice University logo trademarks, or wordmarks are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.