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Energy Glossary

Joule

Official unit for the physical property energy. The abbreviation is the "J".

To understand what 1 Joule is equivalent to you will see a set of examples below:

Example 1
The energy of 1 Joule is invested if you lift 1 kilogram by a height of 0.1 meter (= 10 centimeters or 4 inches).

Example 2
An AAA battery (NiMH, 1.25 Volts, 800 mAh) stores the energy equivalent of 3600 Joule. (1.25 Volts x 0.8 Amperes x 1 hour = 1.25 Volts x 0.8 Amperes x 3600 seconds = 3600 Joule)

Example 3
Climbing a height difference of 1000 metres with a body mass of 75 kilogramms at an efficiency of 25 percent needs

1000 metres x 10 metres / seconds ^2 x 75 kilograms / 0.25 [efficiency!] = 3 000 000 Joule or 3 000 Kilojoule

Example 4
Daily food demand of an adult person with moderate physical activity (today s standard) is roughly 9 000 Kilojoule (= 9 000 000 Joule).

Example 5
Amounts of energy can be compared to each other - let s take a look at Ex. 3 and Ex. 4: If you make a tough walk from a valley to a peak 1000 metres higher you need 30 percent of your daily energy budget. This explains why our brain is crying for food after higher physical activities. A mining worker who works phyiscally has twice the energy demand of an office worker - and usually less body mass.

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