Work and energy

Work and Energy

Energy is an important concept in every day life. It appears as gravitational potential energy of objects raised to a certain height, as elastic potential energy in a stretched rubber band, as kinetic energy of moving objects, or as chemical energy in the food that we eat. Closely associated with energy is the concept of work. Energy is transferred to another system when you do work. Power provides a measure of the energy expended per unit time. Efficiency of machines provides a measure of the energy converted into useful work.

Familiarity with the following terms will help you get the most from this module:

Terms	Definition
Work	The product of a constant force magnitude and the magnitude of the displacement
Joule	The unit of work which is the special name for Newton meter
Energy	The capacity to do work
Potential energy	The energy due to position
Kinetic energy	The energy due to motion
Power	The rate of doing work
Watt	The unit of power which is the special name for Joule per second
Machines	Devices that help us do work
Actual Mechanical Advantage	It determines the number of times a machine multiplies force
Ideal Mechanical Advantage	The ratio of the effort distance to the resistance distance
Efficiency	The ratio of the actual mechanical advantage to the ideal mechanical advantage, or the ratio of the work output to the work input