0.34 Phy1340: angular momentum -- rotational equilibrium

Table of contents

• Preface
  • General
  • Prerequisites
  • Supplemental material
• Discussion
• Example scenarios
  • Weights hanging on a beam
    • Part 1
    • Part 2
  • Beam supported by a diagonal cable
    • Part 1
    • Part 2
    • Part 3
  • A crane scenario
    • Part 1
    • Part 2
    • Part 3
  • Sliding a crate
    • Part 1
    • Part 2
  • Another crane scenario
    • Part 1
    • Part 2
    • Part 3
  • A ladder scenario
    • Part 1
    • Part 2
• Repeat the computations
• Resources
• Miscellaneous

Preface

General

This module is part of a book (or collection) designed to make physics concepts accessible to blind students. The collection is intended to supplement but not to replace thetextbook in an introductory course in high school or college physics.

This module explains rotational equilibrium in a format that is accessible to blind students.

Prerequisites

In addition to an Internet connection and a browser, you will need the following tools (as a minimum) to work through the exercises in these modules:

• A graph board for plotting graphs and vector diagrams ( (External Link) ).
• A protractor for measuring angles ( (External Link) ).
• An audio screen reader that is compatible with your operating system, such as the NonVisual Desktop Access program (NVDA), which is freelyavailable at (External Link) .
• A refreshable Braille display capable of providing a line by line tactile output of information displayed on the computer monitor ( (External Link) ).
• A device to create Braille labels. Will be used to label graphs constructed on the graph board.

The minimum prerequisites for understanding the material in these modules include:

• A good understanding of algebra.
• An understanding of the use of a graph board for plotting graphs and vector diagrams ( (External Link) ).
• An understanding of the use of a protractor for measuring angles ( (External Link) ).
• A basic understanding of the use of sine, cosine, and tangent from trigonometry ( (External Link) ).
• An introductory understanding of JavaScript programming ( (External Link) and (External Link) ).
• An understanding of all of the material covered in the earlier modules in this collection.

Supplemental material

I recommend that you also study the other lessons in my extensive collection of online programming tutorials. You will find a consolidated index at www.DickBaldwin.com .

Discussion

This module will consist of a short discussion followed by a lot of hands-on practical problem solving.

Translational and rotational equilibrium

You learned in an earlier module that an object is in translational equilibrium when the net force acting on it is zero. In other words, the vectorsum of the forces acting on the object must be zero.

However, you also learned in an earlier module that it is possible for the net force to be zero, while the net torque is not zero. If the net torque is notzero, the object would have non-zero acceleration, and therefore would not be in rotational equilibrium.

Be careful when climbing a ladder

When you are climbing a ladder, for example, it would be highly undesirable for the system that includes you and the ladder to not be in rotationalequilibrium.