| 2.
Energy Basics
Archive
of Past Articles for Chapter 2
2005. From
Wikipedia, the free encyclopedia: http://en.wikipedia.org/wiki/Energy
Energy is a
measure of being able to do mechanical
work.[1] ...
The energy
of a physical system is defined
as the amount of mechanical work
that the system can produce if
it changes its state to its reference
state; for example if a liter of
water cools down to 0°C
or if a car hits a tree and decelerates
from 120 km/h to 0 km/h.
Energy of
an object can be in several forms, potential—due
to the position of the object
relative to other objects; kinetic—energy
because of its motion; chemical—due
to chemical bonds between atoms
that make up the substance; electrical—due
to its charge; thermal—due
to its heat; and nuclear—due
to the instability of the nuclei
of its atoms. In the case where
the
"object" is an electromagnetic
wave or light, then radiant energy
can also be defined.
One form of energy
can be readily transformed into
another; for instance, a battery
converts chemical energy into electrical
energy, which can be converted into
thermal energy. Similarly, potential
energy is converted into kinetic
energy of moving water and turbine
in a dam, which in turn transforms
into electric energy by generator.
The law of conservation of energy
states that in a closed system the
total amount of energy, corresponding
to the sum of a system's constituent
energy components, remains constant.
This law follows from translational
symmetry of time (that is, independence
of any physical process on the moment
it started). Some works (thus some
forms of energy) are not easily
measured by the unaided observer....
The term "energy" is also
used in a spiritual or non-scientific
way that cannot be quantified, to
make certain propositions appear
more plausible, by imitating the
scientific terminology. Usually this
has something to do with mystical
and/or healing type references such
as acupuncture and reiki. ...
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