Energy

Energy is the capacity to do work

Energy is the capacity or capability to do work. Energy is used when work is done.

The unit for energy is joule - J, where

1 J = 1 Nm

which is the same unit as for work.

Imperial Units of Energy

  • 1 J = 0.738 ft lb
  • 1 ft lb = 1.356 Nm (J)

Energy forms

There can be several forms of energy, including

  • mechanical energy
  • heat or thermal energy
  • electrical energy
  • chemical energy
  • nuclear energy
  • light energy

Energy Efficiency

Energy efficiency is the ratio between useful energy output and input energy, and can be expressed as

μ = Eo / Ei                         (1)

where

μ = energy efficiency

Eo = useful energy output

Ei = energy input

It is common to state efficiency as a percentage by multiplying (1) with 100.

Example - Energy Efficiency

A lift moves a mass 10 m up with a force of 100 N. The input energy to the lift is 1500 J. The energy efficiency of the lift can be calculated as

μ = 100 (N) 10 (m) / 1500 (J)

    = 0.67 or

    = 67 %

Related Topics

  • Mechanics - Forces, acceleration, displacement, vectors, motion, momentum, energy of objects and more
  • Thermodynamics - Effects of work, heat and energy on systems

Related Documents

Tag Search

  • en: energy efficiency
  • es: eficiencia energ├ętica
  • de: Energieeffizienz

Search the Engineering ToolBox

- "Search is the most efficient way to navigate the Engineering ToolBox!"

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your SketchUp model with the Engineering ToolBox - SketchUp Extension/Plugin - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Translate the Engineering ToolBox!
About the Engineering ToolBox!

close