Skip to ContentGo to accessibility pageKeyboard shortcuts menu
OpenStax Logo
Physics

Key Equations

PhysicsKey Equations
Search for key terms or text.

8.1 Linear Momentum, Force, and Impulse

impulse F net Δt F net Δt
impulse–momentum theorem Δp= F net Δt Δp= F net Δt
linear momentum p=mv p=mv
Newton’s second law in terms of momentum F net = Δp Δt F net = Δp Δt

8.2 Conservation of Momentum

law of conservation of momentum ptot = constant, or ptot = p′tot
conservation of momentum for two objects p1 + p2 = constant, or p1 + p2 = p′1 + p′2
angular momentum L = I ω ω

8.3 Elastic and Inelastic Collisions

conservation of momentum in any collision, including elastic collisionselastic collision m 1 v 1 + m 2 v 2 = m 1 v ′ 1 + m 2 v ′ 2 , m 1 v 1 + m 2 v 2 = m 1 v ′ 1 + m 2 v ′ 2 ,
conservation of momentum in a perfectly inelastic collision m 1 v 1 + m 2 v 2 = ( m 1 + m 2 ) v ′ m 1 v 1 + m 2 v 2 = ( m 1 + m 2 ) v ′
conservation of momentum along x-axis for 2D collisions m 1 v 1 = m 1 v ′ 1 cos θ 1 + m 2 v ′ 2 cos θ 2 m 1 v 1 = m 1 v ′ 1 cos θ 1 + m 2 v ′ 2 cos θ 2
conservation of momentum along y-axis for 2D collisions 0= m 1 v ′ 1 sin θ 1 + m 2 v ′ 2 sin θ 2 0= m 1 v ′ 1 sin θ 1 + m 2 v ′ 2 sin θ 2
PreviousNext
Order a print copy
Citation/Attribution

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 permission.

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute Texas Education Agency (TEA). 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.

Attribution information
  • If you are redistributing all or part of this book in a 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 digital format, then you must include on every digital page view the following attribution:
    Access for free at https://openstax.org/books/physics/pages/1-introduction
Citation information

© Feb 19, 2025 Texas Education Agency (TEA). The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.