# Energy

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## Energy

Energy can be defined as the ability to do work. It exists in many forms and can be changed from one form to another.Here are some examples:

- Nuclear Energy

- Elastic Energy

- Sound Energy

- Light Energy

- Gravitationl Potential Energy

- Kinetic Energy

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## Laws of Conversion energy

All energy transfers follow the law of conversion of energy.

Energy Cannot be created or destroyed just changed in form.

- This means that energy never just "disapears"

- The total amount of energy always stays the same.

i.e. Total Energy Input= Total Energy Output

- Energy that is transfered to unwanted forms  of energy is wasted.

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## Work Done

When energy is transfered work is done.

Work Done = Energy Transfered

Formula:

Work Done = Force x Distance moved in direnction of force or W=FS

Force(f) is measured in newtons (N)

Distance, S is measured in metres (m)

Work done , w is measured in Joules (J)

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## Gravitational Potential Energy

Gravitational Potential Energy is the amount of energy an object has because of its position in a gravitational field.

Formula:

GPE= mass x gravitational field strength x height
Gravitational field strength is 9.8 on earth

Example:
An Osprey with a mass of 2kg flies at a height of 200m above the ground. How much Gravitational Potential Energy does the Osprey have?
GPE=mass x gravitational field strength x height
= 2 x 9.8 x 200

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## Elastic Potential Energy

When a forcce acts to compress or stretch an object, that force does work

Elastic Potential Energy = 1/2 x spring constant x (extension)2

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