Chapter 7: Work, Energy and Power

Doing Work, Transferring Energy

Energy - That which is transferred when a force moves through a distance.

When calculating work done you must consider two factors involved;

* the size of the force - the bigger the force, the greater amount of work you do.

* the distance - the greater the distance, the greater amount of work you have done.

Calculating Work Done

The work done by a force is defined as:

work done = force x the distance moved in the direction of the force or w= f x x

Doing work is a way of transferring energy. For both energy and work the unit is the joule (J)

The amount of work done also gives us the energy transferred: work done = energy transferred

Newtons, Metres and Joules

From the previous eqution (w=f x x ) we see the newton, the metres and the joule are all related. As the newton measures force, the metre distance and Joules work done.

Joule - The amount of work done when a force of 1 Newton moves a distance of 1 metre in the direction of the force.

Force, Distance and Direction

For a force to do work there must be a movement in the direction of the force. Both the force and distance moved in the direction of this force are vector quantities. If the force acts in a distance which is Q to F then to determine the work done we must determine the component of F in the direction.…