Work, energy and power are terms that are used regularly but not always correctly. You often hear the word energy being used when power is meant or you hear power being used when force is what is intended. What do we really mean when we talk about a powerful serve in tennis, or a football player's high work rate or a team that is lacking in energy? In Physics the terms work, energy and power have precise meanings. It is important that you are able to use these terms correctly in your Physics examination. You will also be expected to use them in doing calculations and solving problems. You may wish to print a hard copy for your reference.
Work
Work done is defined as product of the force and the distance over which the force is applied.
Work is done when a force is applied to an object and the object is moved through a distance. For example, when you lift a load you are applying a force over a distance so you are doing work.
When you push a shopping trolley around a supermarket you are applying a force over a distance, therefore you are doing work.
When a car is moving on a motorway, a force is being applied over a distance and work is being done.
- Work done:
- = force x distance
- = W = F x d
- W is measures in joules.
- F is measure in newtons.
- d is measured in metres.
- When work is done, energy is transferred.
Listen to this audio clip to learn about the science of work and energy.
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Learning Zone Scotland
Video clip about potential and kinetic energy.
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