Skip to ContentGo to accessibility page
College Physics

Introduction to Linear Momentum and Collisions

College PhysicsIntroduction to Linear Momentum and Collisions

Figure 8.1 Each rugby player has great momentum, which will affect the outcome of their collisions with each other and the ground. (credit: ozzzie, Flickr)

Chapter Outline

  • 8.1 Linear Momentum and Force
    • Define linear momentum.
    • Explain the relationship between momentum and force.
    • State Newton’s second law of motion in terms of momentum.
    • Calculate momentum given mass and velocity.
  • 8.2 Impulse
    • Define impulse.
    • Describe effects of impulses in everyday life.
    • Determine the average effective force using graphical representation.
    • Calculate average force and impulse given mass, velocity, and time.
  • 8.3 Conservation of Momentum
    • Describe the principle of conservation of momentum.
    • Derive an expression for the conservation of momentum.
    • Explain conservation of momentum with examples.
    • Explain the principle of conservation of momentum as it relates to atomic and subatomic particles.
  • 8.4 Elastic Collisions in One Dimension
    • Describe an elastic collision of two objects in one dimension.
    • Define internal kinetic energy.
    • Derive an expression for conservation of internal kinetic energy in a one dimensional collision.
    • Determine the final velocities in an elastic collision given masses and initial velocities.
  • 8.5 Inelastic Collisions in One Dimension
    • Define inelastic collision.
    • Explain perfectly inelastic collision.
    • Apply an understanding of collisions to sports.
    • Determine recoil velocity and loss in kinetic energy given mass and initial velocity.
  • 8.6 Collisions of Point Masses in Two Dimensions
    • Discuss two dimensional collisions as an extension of one dimensional analysis.
    • Define point masses.
    • Derive an expression for conservation of momentum along x-axis and y-axis.
    • Describe elastic collisions of two objects with equal mass.
    • Determine the magnitude and direction of the final velocity given initial velocity, and scattering angle.
  • 8.7 Introduction to Rocket Propulsion
    • State Newton’s third law of motion.
    • Explain the principle involved in propulsion of rockets and jet engines.
    • Derive an expression for the acceleration of the rocket and discuss the factors that affect the acceleration.
    • Describe the function of a space shuttle.

Introduction to Linear Momentum and Collisions

We use the term momentum in various ways in everyday language, and most of these ways are consistent with its precise scientific definition. We speak of sports teams or politicians gaining and maintaining the momentum to win. We also recognize that momentum has something to do with collisions. For example, looking at the rugby players in the photograph colliding and falling to the ground, we expect their momenta to have great effects in the resulting collisions. Generally, momentum implies a tendency to continue on course—to move in the same direction—and is associated with great mass and speed.

Momentum, like energy, is important because it is conserved. Only a few physical quantities are conserved in nature, and studying them yields fundamental insight into how nature works, as we shall see in our study of momentum.

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 OpenStax, and must distribute any derivative works under the same license.
  • 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/college-physics/pages/1-introduction-to-science-and-the-realm-of-physics-physical-quantities-and-units

  • 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/college-physics/pages/1-introduction-to-science-and-the-realm-of-physics-physical-quantities-and-units

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.

© Mar 3, 2022 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License. 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.