0.20 Phy1180: energy -- potential energy

Table of contents

• Preface
  • General
  • Prerequisites
  • Supplemental material
• General background information
  • Graphic examples of potential energy
  • Potential energy
    • Gravitational potential energy
    • Elastic potential energy
  • Summary
• Sample calculations
• Do the calculations
• 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 potential energy in a format that is accessible to blind sudents.

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 .

General background information

I will begin this explanation with a couple of graphic examples.

Graphic examples of potential energy

Gravitational potential energy

If you find a flat rock with a mass of 10 kg on the ground at a location on the surface of the earth where the ground is flat for miles around, that rockhas little or no potential energy.

A change in potential energy

If you pick that rock up and balance it on a limb of a tree that is 2 meters off the ground, you have done at least two things:

• You have done work on the rock by exerting a force on the rock that displaced it upward by 2 meters. With some simplifying assumptions, we cancalculate that you have done 196.2 joules of work on the rock.
• You have caused the rock to have gravitational potential energy that it did not have in its earlier position on the ground.