Work, Machines, and Energy


Two conditions must be met in order for work to be done:

  1. The object moves
  2. A force must act on the object in the direction the object moves.

In this lesson we look at the concepts required to do work. Additionally we look at simple and complex machines, and forms of energy.


Work is the movement of an object in a direction. Power is the the rate ate which work is done.

Work is made easier by machine. There are simple and complex machines. Compound machines are made up of two or more simple machines.

The number of times a machine multiplies an effort force is its mechanical advantage.

Mechanical efficiency (ME) of a machine compares its work output with its work input.

The formula for mechanical efficiency is:

ME = work output/work input x 100%

Energy is the ability to do work. Energy has many forms.


Complete the Lesson Inquiry. Turn it in or e-mail it to your teacher.

Compound Machine Design

Create a poster (drawing) of a compound machine that will demolish houses. 

The machine will be movable.  Use more than one simple machine.  The machine must be able to be 'reused'.

Write a one paragraph essay describing the compound and how the simple machines are incorporate.

Scan the picture and attach the essay.  Turn the drawing in or e-mail the poster to your teacher.

Done Early...

Find pictures of simple machines and create a collage using PowerPoint.

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Last modified: 5/30/2012