(c) Dr Paul Kinsler. [Acknowledgements & Feedback]

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Energy

The energy of something is a measure of its capacity for doing work. Something with a lot of energy can do a lot of work, something with little energy can only do a little work. There are two sorts of energy:

• kinetic-energy, from either or both rotation (angular-velocity) or linear velocity;
• potential-energy, which is either stored in some way (e.g. stretched spring) or due to the objects position in a field of some kind (e.g. gravity).

If an object with energy E does an amount of work W on a second object, then the first object is left with an energy of (E-W), whilst the second object ends up with W more energy than it started with. This is conservation of energy .

Energy is usually measured in units of Joules (J), although when working with atoms and molecules it is often more convenient to use electron -volts (eV).

19990610 19981020 (c) Paul Kinsler

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XKEYWORD: energy

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