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Work, Energy and Power
When a force moves in the direction along which it acts, work is done.
Work is the process of converting energy.
Energy is the ability to do work.
To calculate the work done by a moving force:
the unit of work or energy is the Newton meter or Joule
If the direction of the displacement is not the same as the direction of the force, we use the component of the force which is parallel to the displacement. For example, when a body is caused to accelerate down an inclined plane by the force of gravity:
Therefore, the more general equation to calculate work done is
where is the angle between the force and the displacement.
Although force and displacement are both vectors, work (or energy) is a scalar quantity.
The Law of Conservation of Energy
Energy is never destroyed, it is just converted from one form to another.
Examples of Energy Conversions
Power is work done per second (or energy converted per second).
unit of power is the Joule per second, Js-1