13
CHAPTER
ENERGYAND POWER
P
owerful cranes lift and
lower structural members
in place. We need energy
to build shelter, to cultivate and
process food, to make goods,
and to maintain our living places
at comfortable settings. To
quantify the requirements to
move objects, to lift objects, or
to heat or cool something,
energy is defined and classified
into different categories. Power
is the time rate of doing work.
The value of power required to
perform a task represents how
fast you want the task done.
If you want a task done in a
shorter period of time, then
more power is required.
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